Specifications: Refills 1 lb. bottles in 1 minute or less so quick. Works with all 20, 30, or 40 pound 50, cylinders. With this adapter you are not able to overfill the smaller bottles, it will only put in the tank as much as it can hold, you are also able to backfill into larger tank if you got in a situation where your larger tank runs dry. Hook up the smaller cylinder with this adapter and it will equalize the pressure between the two tanks. Compared with others, ours has a safety feature. When flow capacity is too high, ours will automatically close at the end. This feature controls the flow capacity of the propane transfer and ensures the tank will never overflow. This protects you from dangerously overfilling your tank while theirs not. Mount Tips: 1. Connect left-hand threaded lug of adapter to tank. 2. Connect right-hand threaded cap of adapter to 1 lb. cylinder (hand tighten). 3. Turn 1 lb. cylinder and tank upside down. 4. Open valve on tank for several minutes until you can no longer hear the propane transfer. Then shut valve off. 5. Return 1 lb. cylinder and tank to upright position. 6. Disconnect smaller 1 lb cylinder first. 7. Inspect 1 lb. cylinder for leaks: Place a small amount of one-half liquid soap one-half water solution on cylinder opening and on relief valve. If bubbles appear, discard smaller cylinder in a safe area. Applications: Propane adapter that allows you to refill small disposable propane tanks with your larger 20-50lb BBQ propane tank. Great for ice fishermen, mountain men, outdoorsmen, and all campers and power outages. Item Name: Propane Refill Adapter Material: Brass Features: Durable, Compact, Easy to Install Length: 2cm x 5.5cm/0.79" x 2.17" (Approx.) Notes: To use adaptor to refill 1 lb. cylinders from 20-40 lb. tank. Important: Always start with an empty cylinder. Before refilling, chill the smaller empty 1 lb. cylinder for 15-20 minutes in the fridge (for best fill). Have full larger tank at room temperature (never exceed 85 Fahrenheit degrees). Due to the light and screen setting difference, the items color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Propane Refill Adapter