Enjoy smooth, seamless lens operation underwater when using AquaTech's 10901 CZ 16-35mm Zoom Gear for the Canon 16-35mm f/2.8 L, f/2.8 L II or f/4 IS Lens. Mount the gear on the zoom ring of your lens, then connect it to the zoom control knob of your AquaTech Delphin or Elite Sport Housing. When you're ready to shoot, you'll be able to zoom the lens back and forth from outside the housing.
Above water: Use AquaTech's P-110 Port with f/2.8 L, and P-120 Port with f/2.8 L II & f/4 IS
Underwater: Use AquaTech's PD-85 Port and P-70 EX Extension Ring with all lenses.