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 housing can be used on small boats, in the surf, while swimming, snorkeling or diving. It`s easy to operate as the camera as its various components and buttons can be operated through the PVC. The U-BZ is specially designed to fit the bulky, professional and semi-professional digital SLR cameras like the Canon EOS 1D series, EOS 5D or the Nikon D1, D2X, D200 and similar cameras. Smaller SLR cameras then the mentioned above can still be used in the housing. The fact that the U-BZ 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. With this housing, a whole new world of applications opens up for your professional digital SLR camera: Inside the housing you can now take the camera safely canoeing, snorkeling or even diving, up to a depth of 20 m / 60 ft. If the optional BF1 lead weight is inserted into the housing, underneath the camera, it becomes even easier to reach the maximum depth. Experienced photographers have confirmed, that the auto focus continue to function perfectly. As you descend, the air is pressed into the camera. Due to this, the pressure inside the housing will remain the same as the surrounding water pressure. (this is the reason why ewa-marine housings are so safe to use: implosions are impossible) Due to this, we have to start the dive with a suitable amount of air inside the housing. The foam pads supplied with the housing are part of this air "reservoir" and additional air should also be blown into the housing, via the valve at the rear, to ensure that the maximum potential volume is being utilised.