The Metal Tripod Collar Mount Ring is designed to provide stability and balance for heavy telephoto lenses, particularly the for AF135 F1.8 Featuring an Arca-compatible dovetail plate, it allows for seamless attachment to various tripod heads. The mount includes multiple 1/4"-20 and 3/8"-16 thread screw holes for direct tripod connection. Made from high-quality aviation aluminum alloy, it is yet robust, ensuring long-lasting performance. With a ring inside diameter of 84mm and a baseplate size of 70mm x 40mm, this mount is perfect for photographers seeking reliable support for their equipment. Specifications: The UNC (Unified National Coarse Thread) : 1/4" & 3/8" Compatibility: Arca- Standard Ring inside diameter: 84mm/3.3inch Baseplate Length: 70mm/2.75inch Baseplate Width: 40mm/1.57inch Color: black Compatible with: For AF135 F1.8 Material: Aluminum Alloy Package Contents: 1 x Lens Tripod Mount Ring Only the above package content, other products are not included. Note: Light reflection 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.