The Zoom Clamp For DSLR Housings is a large diameter clamp designed to be attached to lens zoom rings with a diameter of 3" or less. It's an accessory that comes included with all of Ikelite's DSLR Housings. Thus, this one serves as a spare or replacement for the original that came with your underwater housing. The zoom clamp features grooved tabs that line up with the gear sleeve posts. It also has springs that allow it to be expanded to fit over the zoom ring of the lens.
This clamp may be used on Type 1 or Type 2 lenses; Type 1 lenses have lens openings the same diameter or smaller than the zoom ring, while Type 2's have openings larger in diameter than the zoom ring. The 9059.9 clamp should be used with the #0073.1 sleeve. With a type 2 lens, both the clamp and 0073.1 sleeve must be installed on the lens zoom ring from the back end of the lens, then bayonetted onto the camera body, which is already installed in an Ikelite housing.