The Ewa-Marine U-B 100 housing is specially designed to fit bulky, digital SLR cameras such as the Canon 1Ds, Nikon D3, D300 and other cameras around the same size. Smaller SLR cameras can still be used in the housing. The housing is manufactured from double laminated PVC and has an optical glass port.The lens port is wide in order to accommodate lenses with a large diameter. Use the included C-A 77 adapter for lenses with a 77mm filter thread or the optional C-A 82 adapter for lenses with a 82mm filter thread. All lenses used with this housing must have internal focus.