Opteka Tripod Collar Mount for the Canon EF 70-200mm f/4L USM, EF 300mm f/4L USM, EF 400mm f/5.6L USM SLR Lenses Opteka Brand Tripod Collar for the Canon EF 70-200mm f/4L USM, EF 300mm f/4L USM, & EF 400mm f/5.6L USM SLR Lenses Durable Aluminum Construction Off-White