The Canon Lens Wide Strap B f/EF 300 / 400 mm f/2.8L IS II USM is a carrying strap for your camera lens. It is compatible with the EF 300 mm f/2.8L IS II USM and the EF 400 mm f/2.8L IS II USM super telephoto lenses. The wide strap is made from a tough, strong fabric and features the white Canon logo.