Nuprol 4.0 GBB gas
, also known as Nuprol 4.0 Ultimate Power Black Gas, is an ultra-high performance gas designed for year-round airsoft use, especially in colder temperatures. Its high pressure makes it ideal for gas blowback rifles (GBBRs) and IPSC shooting competitions, though it is not recommended for airsoft replicas with plastic slides. 
Product Details & Features
The Nuprol 4.0 gas is formulated to maintain consistent performance in cold conditions. 
Operating Temperature: The optimal operating range is between 3°C and 20°C (37°F and 68°F).
Performance: It delivers higher pressure than standard green gas, which results in an increase in feet per second (FPS), improved gas blowback efficiency, and a stronger recoil kick.
Composition: It contains a silicone lubricant to treat and maintain rubber seals, helping to prevent rust and corrosion. It is also CFC-free.
Bottle Construction: Each bottle is made from a strong alloy and features a long metal nozzle for a secure fit into magazine valves.
Safety Note: Due to its high power, it is crucial to only use this gas with full metal GBBRs or weapons specifically rated to handle the high pressure to avoid damage to internal components. It should not be used in temperatures above 20°C (68°F) as this can cause damage.