It's a way to mount a Mini Maglite flashlight to the accessory rail on a Nerf Gun. Tested and works great on both a Nerf Strongarm and a Nerf Rampage. On the Nerf Rampage, if you mount this to the front rail, and LoKiki56's model "Nerf Sight - Viseur" to the rear rail, the back of the flashlight will line up really nicely with the sights. You'll feel like you're in Splinter Cell while using this thing, lol.