SUNWAYFOTO brand Arca-Swiss compatible MCP-01 25mm Screw Knob Clamp Kit.2 x 25mm Mini clamps, plus changeable Mate-plate to allow back to back mountingincluding 90° or parallel. 1/4" mounting hole. Very versatile Jaw opening range of 38mm to 41.5mm will accommodate any Arca style plate from various makers including:Really right stuff (RRS), Wimberley, Jobu Design, Arca Swiss, Kirk Enterprises,Markins, etc. Each clamp measures:Length: 25mm. Width: 53mm. Height: 14mm. Weight: 50g. All metal construction. Includes the accessories pictured.