Follow the instructions - SIG SAUER FOXTROT1 TACTICAL WHITE LIGHT

Let's start by saying, unpacking is not straight forward, especially if you want to try to preserve the packaging to return it. The structure is slim compared to Surefire and extremely lightweight with the included CR123a battery installed. The installation onto the pistol is extremely easy and includes a hex key in the form of.....a key. The Cree LED light is bright in each setting and is obvious to discern from each 100, 200, and 300 lumens as you cycle through the selectable output. Of note, user must "press and hold both switches to cycle" through the outputs. Once that output is selected, you can single press to turn it on keeping that selected output or hold the switch for momentary on. I will say ahead, this is NOT a tactical light where speed is your interest or brightness; also, there is no strobe feature! I love that the install was quick and simple; I love that the battery can be installed without removing the assembly. I do not love the very different, push button switch, to switch on. Would I recommend? Absolutely! For the cost, this is a great, lightweight, home-protection and even holster carry light.