The zoom and clamp set is included with all dSLR housings to accommodate larger diameter lenses. A special gear drive sleeve with shorter drive ribs is also included that must be used with this clamp. The #5509.28 clamp set is made for lenses with zoom or focus rings from 2.8" to 3.0" in diameter. If the lens is over 3.0" in diameter, this clamp set must be installed on the lens from the back of the lens before the lens is installed onto the camera body. Large diameter lenses will require installing the lens after sealing the camera body inside the housing. The clamp is installed as described above, then this lens assembly slips into the clear gear sleeve and the lens is attached to the camera body.
The clear gear sleeve is then pushed into place, making certain it is completely meshed with the drive gears. Check that the #5509.28 clamp is operated by the clear gear sleeve and that the sleeve is completely in place so it will not interfere when installing the port. This procedure must be reversed before opening the camera housing. It sounds complicated, but in reality adds only a matter of seconds to the assembly once you understand the process. It actually exposes less of the camera to a drip of water when changing lenses than removal of the entire camera from the housing