The pressure decompression valves can mutual-fill several gastank that are not fully used with each other. When the gastank can not be filled continuously due to the high pressure of the gastank during the filling process, the excess pressure can be decompression from the gastank by pressing the pressure decompression button to continue filling. With the extension rod, it can be used to connect the gaslamp, and the flamepower of the gaslamp can be controlled through the valves. Features: Multiple unused gastanks can be collected to one gastank through the pressure decompression valves for reuse to avoids waste. During the gasfill process, when the pressure is too high to fill, you can press the pressure decompression button to continue. The extension rod is made of fine quality aluminum alloy material, long service time, accurate machining, quick connection of threaded joints, built-in locking device to prevents thegas from spraying. The extension rod can adjust the lamp height. Easy to store and carry. It is more convenient to use lamp outdoors. Specifications: Type: Set A, Set B (optional) Material: aluminum alloy+brass Pressure decompression valves size: 140 * 95 * 16mm Extension rod size: 118 * 16 * 16mm Pressure decompression valves weight: 36g Extension rod size: 47g Package size: Set A: 120 * 50 * 50mm / 4.7 * 2.0 * 2.0in Set B: 120 * 20 * 20mm / 4.7 * 0.8 * 0.8in Package weight: Set A: 88g / 3.1ounce Set B: 50g / 1.8ounce Packing List: Set A: 1 * Pressure Decompression Valves 1 * Extension Rod Set B: 1 * Extension Rod