Wadsn Metal 1500lumens Bright Weapon Light Hunting Tactical Strobe Flashlight Airsoft Scout Light Mounted to 20mm Rail. Press and hold for more than three seconds to convert the’Constant on’ and’Momentary on’ functions to each other. This weapon light has a function , this kind of flashlight lamp is downflow dimming, Product boot lumen 100% output One minute later it was down to 80% Two minutes later it was down to 70% Three minutes later it was down to 60% Four minutes later it was down to 50% Five minutes later it was down to 30% And then constant 30% output. Battery: CR123 or 16340 2/18650 1 (not included). Fit for Left hand or right hand press. Note:The installation of the product is fastened in the form of a buckle, so the part of the buckle point is rubbed and peeled off.