This is the Power Grip (PG-4) winder made by Ricoh for several of their single-lens reflex cameras. It provides a
     better grip for the camera body and the ability to shoot several shots very quickly, great for action, sports or just
     convenience (so you don't miss a shot by forgetting to wind the film)

Features:

          Compatible with Ricoh XR-P, XR-20SP and KR-30SP cameras (I am also selling a Ricoh KR-30SP
          Advances film up to 1.4 frames per second (fast enough for most applications)
          Extra grip makes camera feel more comfortable and secure in your hand
          Works on all shutter speeds, including B (for long exposures)
          Mounts on tripods
          Requires 2 AAA batteries