The Z-rail Z-lock attaches to the top of your camera or camera handle with two ¼” 20 screws (Included). It is compatible with Epic/Scarlet, Sony F3, Black Magic camera, Panasonic AF100 and others. The Z-rail section has a ¼” 20 screw mount in the center for a Noga arm or other accessories. The Z-lock section attaches to the Z-rail portion with a screw. It can rotate 90 degrees for accessory placement. The Z-lock can accept a female 15mm rod or Zacuto articulating arm. It is ideal for mounting an EVF off of the top handle of a F3 or AF100 where rod space under the lens is limited. Check out the EVF Top Mount