By connecting Ikelite's 5515.02 Zoom Sleeve to the zoom ring of your Olympus M.ZUIKO 12-50mm f/3.5-6.3 ED EZ lens, you will enable zoom control when the lens is inside Ikelite's 5516.15 Underwater DLM Dome Port. Place the required clamp around the ring and slide the sleeve over the clamp. Make sure that the teeth at the edge of the sleeve mesh with the housing's zoom gear, in order to allow for smooth operation underwater. The DLM Dome Port is compatible with select Ikelite housings for mirrorless and DSLR cameras. For full lens and port compatibility, see the Port Chart..