The JJC RGA-2 Lens Hood & Adapter is a two-piece set of lens accessories for the RICOH GR Digital III & IV camera. After you remove the camera's ring cap, the adapter twists & clicks onto the body, bayonet-style.
The adapter allows you to screw in filters that have a 43mm diameter. You can also attach the lens hood to the front of the adapter, whether or not there is a filter attached. The lens hood features a ridged interior surface that's designed to deflect light.