Ewa Marine, the ORIGINAL Underwater Housing manufacturer has been an industry innovator, trusted by organizations including Disney, and the U.S. Military to protect their photography and video equipment for over 45 years. The U-BZ 100 is a special version of the U-BZ housing. It has a wider frontglass and allows in combination with the C-A 77 adapter (supplied with the housing) and C-A 82 (available as an accessory from your dealer) adapter the use of lenses with a filter thread of 77 and 82mm. This means you can use your professional digital SLR camera like the Nikon D1, D2H, D2X, D200 and similar cameras, with most of the professional zoom lenses currently on the market. The fact that the U-BZ 100 can be used with up to 300m lenses, makes it speciffically interesting for canoeists and other out door photographers that want to take pictures of birds and other wild life while in or on the water. Lenses with a smaller filter diameter can also be used in this housing as long as they have an internal focus. You just need the right step-up ring. The autofocus adapter (AV110) is not included in delivery as it is not needed for this housing. The U-BZ 100 housing is manufactured from double laminated PVC and has an integrated, optically neutral flat glass port. You can also use the internal flash. It has a pair of non-corrosive and seawater resistant clamping rails which fit together for perfect sealing. They tighten by means of three screw knobs. It is supplied in a handy yellow carry-case which has a water-proof interior.