The Sunwayfoto DDC-42L Screw-Knob Dovetail Clamp is an Arca-type compatible clamp that features an extended locking knob and a removable bubble level. There is a numbered scale on both sides of the clamp to help balance your camera with easy repeatability. The clamp is CNC machined from aluminum and has a satin anodized finish to provide abrasion and corrosion resistance. A 3/8″-16 to 1/4″-20 bushing reducer and an Allen wrench are included with the clamp.