Pinty 100% Brass Propane Refill Adapter for 1lb Small LP Gas Cylinder Tank Auto-Close Protect Used to refill 1lb or smaller propane cylinders from 20-40lbs tanks. The safest refill adapter on the market; Automatically balances pressure in both tanks; Made from solid brass, built to last a lifetime. Automatically closes and stops refilling when flow capacity is maxed out, protecting you from dangerous overfill. Deeper inner threads, helping to screw the adapter in further, preventing potential gas leaks. A must-have for campers, hunters, outdoors-men, fishermen etc.