This gear allows the photographer to use the manual focus dial on this lens, via the zoom wheel on the Olympus PEN Housings. It fits all Olympus PEN underwater housings from the PT-EP01 to PT-EP10 and all models in-between.
The gear simply slips over the 60mm lens barrel and then engages with the zoom gear wheel in the housing. Auto Focus can still be selected from the menu during a dive and switched from manual to auto-focus at any time.
It is a great accesssory for shooting macro and ultra macro with wet lenses, as the focus can be locked and then held at a point suited to your subject size, focus can be fine tuned via the camera LCD.