Steam player countSteam14,781
Tarkov
AK-12 gas tube

AK-12 gas tube

AK-12 gas
Last
25,000 ₽
Min 24h
—
Avg 24h
32,500 ₽
Flea offers
2
↑0 ↓0 /day
Profit / limit
+93,225 ₽
+18,645 ₽/pc × 5
No fresh item data
Base price
2,384 ₽
Buy
Prapor
3,243 ₽
Prapor LL3
limit 5
Trader buyback
Mechanic
1,072 ₽
Mechanic
Trader buyback
Prapor
953 ₽
Prapor
Trader buyback
Ref
953 ₽
Ref
Trader buyback
Skier
929 ₽
Skier
Trader buyback
Peacekeeper
858 ₽
Peacekeeper
Trader buyback
Fence
572 ₽
Fence
How profit is calculated
Buy / item3,243 ₽
Estimated sell / item25,000 ₽
Fee / item3,112 ₽
Profit / item18,645 ₽

Restock profit = profit per item × the full limit of the selected trader offer. Hideout fee discounts are excluded. Market activity reflects changes in prices and listings, not completed sales.

Stats

Weight0.12 kg
Size1×1
Recoil modifier-1%

Price chart

The line shows interval averages. Times are UTC.053,920107,84019/05/2606/06/2624/06/2612/07/2629/07/2616/08/2603/09/2621/09/2609/10/2627/10/26036Average offer count: 1 12/08/2026, 00:00:00 — 12/08/2026, 23:59:59 UTCAverage offer count: 1 13/08/2026, 00:00:00 — 13/08/2026, 23:59:59 UTCAverage offer count: 1 14/08/2026, 00:00:00 — 14/08/2026, 23:59:59 UTCAverage offer count: 1 15/08/2026, 00:00:00 — 15/08/2026, 23:59:59 UTCAverage offer count: 2 16/08/2026, 00:00:00 — 16/08/2026, 23:59:59 UTCAverage offer count: 1 17/08/2026, 00:00:00 — 17/08/2026, 23:59:59 UTCAverage offer count: 1 18/08/2026, 00:00:00 — 18/08/2026, 23:59:59 UTCAverage offer count: 1 19/08/2026, 00:00:00 — 19/08/2026, 23:59:59 UTCAverage offer count: 1 20/08/2026, 00:00:00 — 20/08/2026, 23:59:59 UTCAverage offer count: 1 21/08/2026, 00:00:00 — 21/08/2026, 23:59:59 UTCAverage offer count: 1 22/08/2026, 00:00:00 — 22/08/2026, 23:59:59 UTCAverage offer count: 6 23/08/2026, 00:00:00 — 23/08/2026, 23:59:59 UTCAverage offer count: 4 24/08/2026, 00:00:00 — 24/08/2026, 23:59:59 UTCAverage offer count: 4 25/08/2026, 00:00:00 — 25/08/2026, 23:59:59 UTCAverage offer count: 3 26/08/2026, 00:00:00 — 26/08/2026, 23:59:59 UTCAverage offer count: 1 27/08/2026, 00:00:00 — 27/08/2026, 23:59:59 UTCAverage offer count: 1 28/08/2026, 00:00:00 — 28/08/2026, 23:59:59 UTCAverage offer count: 1 29/08/2026, 00:00:00 — 29/08/2026, 23:59:59 UTCAverage offer count: 1 30/08/2026, 00:00:00 — 30/08/2026, 23:59:59 UTCAverage offer count: 1 31/08/2026, 00:00:00 — 31/08/2026, 23:59:59 UTCAverage offer count: 1 01/09/2026, 00:00:00 — 01/09/2026, 23:59:59 UTCAverage offer count: 1 02/09/2026, 00:00:00 — 02/09/2026, 23:59:59 UTCAverage offer count: 2 03/09/2026, 00:00:00 — 03/09/2026, 23:59:59 UTCAverage offer count: 3 04/09/2026, 00:00:00 — 04/09/2026, 23:59:59 UTCAverage offer count: 1 05/09/2026, 00:00:00 — 05/09/2026, 23:59:59 UTCAverage offer count: 1 06/09/2026, 00:00:00 — 06/09/2026, 23:59:59 UTCAverage offer count: 1 07/09/2026, 00:00:00 — 07/09/2026, 23:59:59 UTCAverage offer count: 1 08/09/2026, 00:00:00 — 08/09/2026, 23:59:59 UTCAverage offer count: 1 09/09/2026, 00:00:00 — 09/09/2026, 23:59:59 UTCAverage offer count: 1 10/09/2026, 00:00:00 — 10/09/2026, 23:59:59 UTCAverage offer count: 1 11/09/2026, 00:00:00 — 11/09/2026, 23:59:59 UTCAverage offer count: 1 12/09/2026, 00:00:00 — 12/09/2026, 23:59:59 UTCAverage offer count: 1 13/09/2026, 00:00:00 — 13/09/2026, 23:59:59 UTCAverage offer count: 1 14/09/2026, 00:00:00 — 14/09/2026, 23:59:59 UTCAverage offer count: 1 15/09/2026, 00:00:00 — 15/09/2026, 23:59:59 UTCAverage offer count: 1 16/09/2026, 00:00:00 — 16/09/2026, 23:59:59 UTCAverage offer count: 1 17/09/2026, 00:00:00 — 17/09/2026, 23:59:59 UTCAverage offer count: 1 18/09/2026, 00:00:00 — 18/09/2026, 23:59:59 UTCAverage offer count: 1 19/09/2026, 00:00:00 — 19/09/2026, 23:59:59 UTCAverage offer count: 1 20/09/2026, 00:00:00 — 20/09/2026, 23:59:59 UTCAverage offer count: 1 21/09/2026, 00:00:00 — 21/09/2026, 23:59:59 UTCAverage offer count: 1 22/09/2026, 00:00:00 — 22/09/2026, 23:59:59 UTCAverage offer count: 1 23/09/2026, 00:00:00 — 23/09/2026, 23:59:59 UTCAverage offer count: 1 24/09/2026, 00:00:00 — 24/09/2026, 23:59:59 UTCAverage offer count: 1 25/09/2026, 00:00:00 — 26/09/2026, 00:05:40 UTCAverage offer count: 1 27/09/2026, 00:05:43 — 27/09/2026, 03:35:36 UTCAverage offer count: 1 28/09/2026, 00:01:43 UTCAverage offer count: 1 29/09/2026, 00:01:51 UTCAverage offer count: 1 30/09/2026, 00:01:57 UTCAverage offer count: 1 01/10/2026, 00:02:06 UTCAverage offer count: 1 02/10/2026, 00:02:10 UTCAverage offer count: 4.5 02/10/2026, 05:21:53 — 03/10/2026, 01:21:56 UTCAverage offer count: 1.29 03/10/2026, 03:21:55 — 04/10/2026, 01:21:58 UTCAverage offer count: 1 04/10/2026, 03:21:59 — 05/10/2026, 00:02:14 UTCAverage offer count: 1 06/10/2026, 00:02:25 UTCAverage offer count: 1 07/10/2026, 00:02:32 — 07/10/2026, 14:22:16 UTCAverage offer count: 1 08/10/2026, 00:02:31 UTCAverage offer count: 1 09/10/2026, 00:07:29 UTCAverage offer count: 1 10/10/2026, 00:07:28 UTCAverage offer count: 1 11/10/2026, 00:07:31 — 11/10/2026, 10:27:22 UTCAverage offer count: 1 12/10/2026, 00:07:36 UTCAverage offer count: 1 13/10/2026, 00:04:36 UTCAverage offer count: 1 14/10/2026, 00:04:49 UTCAverage offer count: 1.67 14/10/2026, 16:24:38 — 15/10/2026, 00:04:51 UTCAverage offer count: 2 15/10/2026, 16:24:38 — 16/10/2026, 00:04:46 UTCAverage offer count: 2 17/10/2026, 00:04:48 UTCAverage offer count: 1.5 17/10/2026, 20:24:43 — 18/10/2026, 00:24:43 UTCAverage offer count: 1 19/10/2026, 00:04:53 UTCAverage offer count: 1 19/10/2026, 10:24:46 — 20/10/2026, 00:04:54 UTCAverage offer count: 1 20/10/2026, 16:24:48 — 21/10/2026, 00:04:58 UTCAverage offer count: 1 22/10/2026, 00:04:59 UTCAverage offer count: 1.11 22/10/2026, 08:54:51 — 23/10/2026, 02:44:53 UTCAverage offer count: 1 23/10/2026, 04:44:53 — 24/10/2026, 00:44:55 UTCAverage offer count: 2 24/10/2026, 08:44:54 — 25/10/2026, 00:05:03 UTCAverage offer count: 2 25/10/2026, 08:44:57 — 26/10/2026, 00:05:09 UTCAverage offer count: 2 27/10/2026, 00:01:00 UTCAverage price: 2,222 ₽ Price range: 2,222 – 2,222 ₽ 19/05/2026, 00:00:00 — 19/05/2026, 23:59:59 UTCAverage price: 12,222 ₽ Price range: 12,222 – 12,222 ₽ 01/06/2026, 00:00:00 — 01/06/2026, 23:59:59 UTCAverage price: 56,667 ₽ Price range: 50,000 – 56,667 ₽ 06/06/2026, 00:00:00 — 06/06/2026, 23:59:59 UTCAverage price: 43,353 ₽ Price range: 25,000 – 43,353 ₽ 07/06/2026, 00:00:00 — 07/06/2026, 23:59:59 UTCAverage price: 37,599 ₽ Price range: 28,888 – 37,599 ₽ 08/06/2026, 00:00:00 — 08/06/2026, 23:59:59 UTCAverage price: 42,222 ₽ Price range: 40,000 – 42,222 ₽ 09/06/2026, 00:00:00 — 09/06/2026, 23:59:59 UTCAverage price: 35,000 ₽ Price range: 30,000 – 35,000 ₽ 12/06/2026, 00:00:00 — 12/06/2026, 23:59:59 UTCAverage price: 40,000 ₽ Price range: 40,000 – 40,000 ₽ 13/06/2026, 00:00:00 — 13/06/2026, 23:59:59 UTCAverage price: 30,495 ₽ Price range: 2,598 – 30,495 ₽ 14/06/2026, 00:00:00 — 14/06/2026, 23:59:59 UTCAverage price: 44,444 ₽ Price range: 44,443 – 44,444 ₽ 15/06/2026, 00:00:00 — 15/06/2026, 23:59:59 UTCAverage price: 84,091 ₽ Price range: 44,444 – 84,091 ₽ 16/06/2026, 00:00:00 — 16/06/2026, 23:59:59 UTCAverage price: 48,627 ₽ Price range: 19,000 – 48,627 ₽ 17/06/2026, 00:00:00 — 17/06/2026, 23:59:59 UTCAverage price: 5,000 ₽ Price range: 5,000 – 5,000 ₽ 19/06/2026, 00:00:00 — 19/06/2026, 23:59:59 UTCAverage price: 2,500 ₽ Price range: 2,500 – 2,500 ₽ 26/06/2026, 00:00:00 — 26/06/2026, 23:59:59 UTCAverage price: 30,000 ₽ Price range: 30,000 – 30,000 ₽ 27/06/2026, 00:00:00 — 27/06/2026, 23:59:59 UTCAverage price: 40,000 ₽ Price range: 40,000 – 40,000 ₽ 29/06/2026, 00:00:00 — 29/06/2026, 23:59:59 UTCAverage price: 26,667 ₽ Price range: 10,000 – 26,667 ₽ 01/07/2026, 00:00:00 — 01/07/2026, 23:59:59 UTCAverage price: 27,807 ₽ Price range: 20,000 – 27,807 ₽ 02/07/2026, 00:00:00 — 02/07/2026, 23:59:59 UTCAverage price: 15,000 ₽ Price range: 15,000 – 15,000 ₽ 03/07/2026, 00:00:00 — 03/07/2026, 23:59:59 UTCAverage price: 2,222 ₽ Price range: 2,222 – 2,222 ₽ 07/07/2026, 00:00:00 — 07/07/2026, 23:59:59 UTCAverage price: 2,500 ₽ Price range: 2,500 – 2,500 ₽ 08/07/2026, 00:00:00 — 08/07/2026, 23:59:59 UTCAverage price: 6,666 ₽ Price range: 6,666 – 6,666 ₽ 02/08/2026, 00:00:00 — 02/08/2026, 23:59:59 UTCAverage price: 100,000 ₽ Price range: 100,000 – 100,000 ₽ 05/08/2026, 00:00:00 — 05/08/2026, 23:59:59 UTCAverage price: 100,000 ₽ Price range: 100,000 – 100,000 ₽ 06/08/2026, 00:00:00 — 06/08/2026, 23:59:59 UTCAverage price: 80,500 ₽ Price range: 80,000 – 80,500 ₽ 08/08/2026, 00:00:00 — 08/08/2026, 23:59:59 UTCAverage price: 12,000 ₽ Price range: 12,000 – 12,000 ₽ 10/08/2026, 00:00:00 — 10/08/2026, 23:59:59 UTCAverage price: 12,000 ₽ Price range: 12,000 – 12,000 ₽ 12/08/2026, 00:00:00 — 12/08/2026, 23:59:59 UTCAverage price: 12,000 ₽ Price range: 12,000 – 12,000 ₽ 13/08/2026, 00:00:00 — 13/08/2026, 23:59:59 UTCAverage price: 12,000 ₽ Price range: 12,000 – 12,000 ₽ 14/08/2026, 00:00:00 — 14/08/2026, 23:59:59 UTCAverage price: 12,000 ₽ Price range: 12,000 – 12,000 ₽ 15/08/2026, 00:00:00 — 15/08/2026, 23:59:59 UTCAverage price: 11,400 ₽ Price range: 5,000 – 20,000 ₽ 16/08/2026, 00:00:00 — 16/08/2026, 23:59:59 UTCAverage price: 20,556 ₽ Price range: 20,000 – 25,000 ₽ 17/08/2026, 00:00:00 — 17/08/2026, 23:59:59 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 18/08/2026, 00:00:00 — 18/08/2026, 23:59:59 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 19/08/2026, 00:00:00 — 19/08/2026, 23:59:59 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 20/08/2026, 00:00:00 — 20/08/2026, 23:59:59 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 21/08/2026, 00:00:00 — 21/08/2026, 23:59:59 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 22/08/2026, 00:00:00 — 22/08/2026, 23:59:59 UTCAverage price: 36,944 ₽ Price range: 20,000 – 67,676 ₽ 23/08/2026, 00:00:00 — 23/08/2026, 23:59:59 UTCAverage price: 31,818 ₽ Price range: 20,000 – 33,000 ₽ 24/08/2026, 00:00:00 — 24/08/2026, 23:59:59 UTCAverage price: 33,000 ₽ Price range: 33,000 – 33,000 ₽ 25/08/2026, 00:00:00 — 25/08/2026, 23:59:59 UTCAverage price: 18,000 ₽ Price range: 3,000 – 33,000 ₽ 26/08/2026, 00:00:00 — 26/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 27/08/2026, 00:00:00 — 27/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 28/08/2026, 00:00:00 — 28/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 29/08/2026, 00:00:00 — 29/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 30/08/2026, 00:00:00 — 30/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 31/08/2026, 00:00:00 — 31/08/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 01/09/2026, 00:00:00 — 01/09/2026, 23:59:59 UTCAverage price: 46,762 ₽ Price range: 3,000 – 90,000 ₽ 02/09/2026, 00:00:00 — 02/09/2026, 23:59:59 UTCAverage price: 31,681 ₽ Price range: 10,000 – 34,440 ₽ 03/09/2026, 00:00:00 — 03/09/2026, 23:59:59 UTCAverage price: 27,407 ₽ Price range: 7,777 – 33,000 ₽ 04/09/2026, 00:00:00 — 04/09/2026, 23:59:59 UTCAverage price: 33,000 ₽ Price range: 33,000 – 33,000 ₽ 05/09/2026, 00:00:00 — 05/09/2026, 23:59:59 UTCAverage price: 23,000 ₽ Price range: 3,000 – 33,000 ₽ 06/09/2026, 00:00:00 — 06/09/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 07/09/2026, 00:00:00 — 07/09/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 08/09/2026, 00:00:00 — 08/09/2026, 23:59:59 UTCAverage price: 3,000 ₽ Price range: 3,000 – 3,000 ₽ 09/09/2026, 00:00:00 — 09/09/2026, 23:59:59 UTCAverage price: 15,750 ₽ Price range: 3,000 – 40,000 ₽ 10/09/2026, 00:00:00 — 10/09/2026, 23:59:59 UTCAverage price: 10,000 ₽ Price range: 10,000 – 10,000 ₽ 11/09/2026, 00:00:00 — 11/09/2026, 23:59:59 UTCAverage price: 10,000 ₽ Price range: 10,000 – 10,000 ₽ 12/09/2026, 00:00:00 — 12/09/2026, 23:59:59 UTCAverage price: 4,666 ₽ Price range: 3,333 – 10,000 ₽ 13/09/2026, 00:00:00 — 13/09/2026, 23:59:59 UTCAverage price: 3,333 ₽ Price range: 3,333 – 3,333 ₽ 14/09/2026, 00:00:00 — 14/09/2026, 23:59:59 UTCAverage price: 3,333 ₽ Price range: 3,333 – 3,333 ₽ 15/09/2026, 00:00:00 — 15/09/2026, 23:59:59 UTCAverage price: 3,333 ₽ Price range: 3,333 – 3,333 ₽ 16/09/2026, 00:00:00 — 16/09/2026, 23:59:59 UTCAverage price: 6,389 ₽ Price range: 3,333 – 10,000 ₽ 17/09/2026, 00:00:00 — 17/09/2026, 23:59:59 UTCAverage price: 5,000 ₽ Price range: 5,000 – 5,000 ₽ 18/09/2026, 00:00:00 — 18/09/2026, 23:59:59 UTCAverage price: 5,000 ₽ Price range: 5,000 – 5,000 ₽ 19/09/2026, 00:00:00 — 19/09/2026, 23:59:59 UTCAverage price: 5,000 ₽ Price range: 5,000 – 5,000 ₽ 20/09/2026, 00:00:00 — 20/09/2026, 23:59:59 UTCAverage price: 5,000 ₽ Price range: 5,000 – 5,000 ₽ 21/09/2026, 00:00:00 — 21/09/2026, 23:59:59 UTCAverage price: 4,121 ₽ Price range: 3,242 – 5,000 ₽ 22/09/2026, 00:00:00 — 22/09/2026, 23:59:59 UTCAverage price: 2,414 ₽ Price range: 2,000 – 3,242 ₽ 23/09/2026, 00:00:00 — 23/09/2026, 23:59:59 UTCAverage price: 2,000 ₽ Price range: 2,000 – 2,000 ₽ 24/09/2026, 00:00:00 — 24/09/2026, 23:59:59 UTCAverage price: 2,000 ₽ Price range: 2,000 – 2,000 ₽ 25/09/2026, 00:00:00 — 26/09/2026, 00:05:40 UTCAverage price: 3,777.5 ₽ Price range: 2,000 – 5,555 ₽ 27/09/2026, 00:05:43 — 27/09/2026, 03:35:36 UTCAverage price: 5,555 ₽ Price range: 5,555 – 5,555 ₽ 28/09/2026, 00:01:43 UTCAverage price: 5,555 ₽ Price range: 5,555 – 5,555 ₽ 29/09/2026, 00:01:51 UTCAverage price: 5,555 ₽ Price range: 5,555 – 5,555 ₽ 30/09/2026, 00:01:57 UTCAverage price: 5,555 ₽ Price range: 5,555 – 5,555 ₽ 01/10/2026, 00:02:06 UTCAverage price: 5,555 ₽ Price range: 5,555 – 5,555 ₽ 02/10/2026, 00:02:10 UTCAverage price: 32,948 ₽ Price range: 18,888 – 50,000 ₽ 02/10/2026, 05:21:53 — 03/10/2026, 01:21:56 UTCAverage price: 11,277.86 ₽ Price range: 5,000 – 20,000 ₽ 03/10/2026, 03:21:55 — 04/10/2026, 01:21:58 UTCAverage price: 10,000 ₽ Price range: 10,000 – 10,000 ₽ 04/10/2026, 03:21:59 — 05/10/2026, 00:02:14 UTCAverage price: 10,000 ₽ Price range: 10,000 – 10,000 ₽ 06/10/2026, 00:02:25 UTCAverage price: 6,611 ₽ Price range: 3,222 – 10,000 ₽ 07/10/2026, 00:02:32 — 07/10/2026, 14:22:16 UTCAverage price: 3,222 ₽ Price range: 3,222 – 3,222 ₽ 08/10/2026, 00:02:31 UTCAverage price: 3,222 ₽ Price range: 3,222 – 3,222 ₽ 09/10/2026, 00:07:29 UTCAverage price: 3,222 ₽ Price range: 3,222 – 3,222 ₽ 10/10/2026, 00:07:28 UTCAverage price: 3,211 ₽ Price range: 3,200 – 3,222 ₽ 11/10/2026, 00:07:31 — 11/10/2026, 10:27:22 UTCAverage price: 3,200 ₽ Price range: 3,200 – 3,200 ₽ 12/10/2026, 00:07:36 UTCAverage price: 3,200 ₽ Price range: 3,200 – 3,200 ₽ 13/10/2026, 00:04:36 UTCAverage price: 3,200 ₽ Price range: 3,200 – 3,200 ₽ 14/10/2026, 00:04:49 UTCAverage price: 29,258.67 ₽ Price range: 28,888 – 30,000 ₽ 14/10/2026, 16:24:38 — 15/10/2026, 00:04:51 UTCAverage price: 28,888 ₽ Price range: 28,888 – 28,888 ₽ 15/10/2026, 16:24:38 — 16/10/2026, 00:04:46 UTCAverage price: 28,888 ₽ Price range: 28,888 – 28,888 ₽ 17/10/2026, 00:04:48 UTCAverage price: 11,600 ₽ Price range: 3,200 – 20,000 ₽ 17/10/2026, 20:24:43 — 18/10/2026, 00:24:43 UTCAverage price: 20,000 ₽ Price range: 20,000 – 20,000 ₽ 19/10/2026, 00:04:53 UTCAverage price: 11,111 ₽ Price range: 11,111 – 11,111 ₽ 19/10/2026, 10:24:46 — 20/10/2026, 00:04:54 UTCAverage price: 39,888 ₽ Price range: 39,888 – 39,888 ₽ 20/10/2026, 16:24:48 — 21/10/2026, 00:04:58 UTCAverage price: 39,888 ₽ Price range: 39,888 – 39,888 ₽ 22/10/2026, 00:04:59 UTCAverage price: 61,997.33 ₽ Price range: 23,988 – 80,000 ₽ 22/10/2026, 08:54:51 — 23/10/2026, 02:44:53 UTCAverage price: 20,000 ₽ Price range: 20,000 – 20,000 ₽ 23/10/2026, 04:44:53 — 24/10/2026, 00:44:55 UTCAverage price: 27,083.25 ₽ Price range: 25,000 – 33,333 ₽ 24/10/2026, 08:44:54 — 25/10/2026, 00:05:03 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 25/10/2026, 08:44:57 — 26/10/2026, 00:05:09 UTCAverage price: 25,000 ₽ Price range: 25,000 – 25,000 ₽ 27/10/2026, 00:01:00 UTC

Purple: price, ₽; gray: offer count. Lines show interval averages; the band shows the price range. Times are UTC.

Description

A standard-issue gas tube for AK-12 automatic rifles. Gas tubes channel the travel direction of gas piston.