More info On this please ^^^
As mentioned it is an Inforce WML. Actually, now that I look at that picture it may be a Chinese knock-off I picked up for $50 - but don't waste your money on that - buy the real think. The real Inforce is top quality, also very compact, easy to use and can literallly be installed or removed in seconds. All you need is 3 picatinny rail slots, the mount is built-in to the flashlight.
Mounted as shown in the picture it is super easy to activate with the thumb of your left hand and it illuminates the front sight as well as the target.