Compatibility: This set of 2 C-clamps fits desktops and tables up to 1.8' in thickness. Each clamp provides 1/4'-20 thread holes and one 3/8'-16 thread hole for multiple mounting options. Please Note: Not meant for use on chairs Versatile Use: Great for clamping your camera or video arm to a tabletop for live streaming or creative content creation. The universal design makes these clamps ideal for many uses, attaching to desks, carts, benches, worktables, and more