Bridge- Mobile Phone MountThe backbone of the Smart Z Finder, the Bridge provides a mounting base for your phone. The adjustable clamp will stretch or shrink to accommodate your phones size and lock in place with the red knob. The Bridge combined with the Accessory Rail has an abundance of places to mount accessories with: 8 Cold Shoes 3 NATO Rails 3 NATO Bi Directional Rails (mounts in either direction) 11 1 4" 20 Mounting holes 1 3 8" 16 Mounting hole 3 Arca Mounts