Made of aluminum, CNC precisely machined, hollow-out weight reduction design, polished and surface anodized finish, with stainless steel screw. Positioning by the switch and bayonet. Cannot be rotated. All the corners are rounded. The inside is covered with plastic film to prevent wear. Inner diameter is about 82mm, width is about 18mm; bottom is added quick release plate feature, plate length is about 65mm, with 1/4 and 3/8 screw holes and stainless steel anti-slip screw. Bottom with a starndard Arca-Swiss dovetail, compatible with Arca Swiss, RRS, kirk, Wimberley, Markins, , , , ... with AS stardard. Applicable to: 100-400mm F5-6.3 OS (E-mount) 105mm F1.4 HSM Art (EF/FX/FE/L-mount) Name: Tripod Mount Ring Colour: Black Material: Aluminum Package Contents: 1 * Tripod Mount Ring IS-SM105ART Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.