DSLRKIT Tripod Mount Ring B (W) for Canon 70-200mm f/2.8L IS II USM & EF 100-400mm f/4.5-5.6L IS USM The perfect color as the original lens. Advanced CNC processing,High quality aluminum baking painted surface. Suitable for Canon EF 70-200mm f/2.8L USM, Canon EF 70-200mm f/2.8L IS USM, Canon EF 70-200mm f/2.8L IS II USM, Canon EF 100-400mm f/4.5-5.6L IS USM. Product specifications: Ring inner diameter: 78mm. Ring width: 18mm. Ring thickness: 4.2-7mm. Color: White. The UNC (Unified National Coarse Thread) is 1/4" and 3/8".