Andoer 38mm Aluminum Screw Knob Mini Quick Release Clamp Compatible with Arca Swiss for 38mm QR Plate CNC precision machining, surface anode anti-oxidation treatment. The body and washer is made of aluminium alloy and copper. When loose the screw, you can adjust the width of clamp. Compatible with AS quick release plate, such as RRS / ARCASWISS / KIRK / Wimberley / MARKINS / SUNWAYFOTO / kangrinpoche / BENRO / SIRUI etc