The tethe rmate for mac book 17” and other similar sized laptop s offers a simple and portable solution for shooting direct to your laptop on location. The 22” x 15.7” (560mm x 400mm) size includes 1/4"-20 and 3/8"-16 female threads on its underside to mount directly on a tripod or any equipment that comes with1/4"-20 and 3/8"-16 male threads. Three mounting slots under the portable plate make it easy to connect additional accessories withthe u-shaped sliding plate. The spring located knob is also included to keep the u-shaped sliding plate securely in place.