The ProMediaGear 1/4"-20 Captive Thumbscrew is designed with a knurled grip to enable attaching ProMediaGear brackets and plates into place without use of any tools. Compatible brackets/plates include the Arca Swiss Type Bracket Clamp and the Flash Bracket Plate for Boomerang. The head of this screw protrudes past the dovetails of most Arca-Swiss type plates and interferes with securing into quick release plates, but otherwise this screw is an efficient alternative to the Allen type screws that come with ProMediaGear gear.