CNC machined from light weight aircraft grade aluminum Satin Anodized Surface provides improved abrasion and corrosion resistance. Arca style dovetail groove, can be used as a lens plate Dual stop safety screws (includes allen wrench). Decreases the overall height of the lens. Dovetail Length: 80mm. Width: 39mm. Height: 30mm. Net Weight: 78g. Mounting Thread: UNC1/4". For Nikon 70-200mm f/2.8G ED VR II. Compatible with all Arca style clamps inc Really Right Stuff lever clamps.