Adjustable Pro Clamp for Round Tube and Flat Surfaces. Adjustable jaw easily opens up to 2.5" and closes with twist handle. Includes wedge for clamping onto flat surfaces. For photographers (video/photo/light applications), it also includes a dual locking 5/8" hexagonal female receiver for studs and arms plus a snap-in 5/8" pin that will accept many small light fixtures. It has 1/4-20 female threads for easy mounting. Includes: - Pro Clamp - Flat Surface Insert - Dual Locking 5/8 Hexagonal Stud - Mini Snap-In 5/8 Pin Also available with Loc-Line Connector.