Sea Frogs Zoom Gear for Sony E16-50 f3.5-5.6 PZ OSS LensThe Zoom Gear for Sony E16 50 f3. 5 5. 6 PZ OSS Lens allows access to manual zoom function in underwater housings. It mounts onto the lens's zoom ring and controls it via the housing's zoom dial. Fits Sea Frogs housings with 90 mount. Compatible with most Sea Frogs dome and flat ports (excluding A6xxx and RX1xx housings). How It Works: Engages the Lens The zoom gear, typically a ridged or toothed ring, wraps around the zoom ring of the lens.