The Spintec RD deflects rain and snow instantly by spinning a specially produced Tiffen glass filter 3000 times per minute. The spinning glass creates both a centrifugal effect which instantly removes rain drops (and even water splashes) and a vacuum effect which removes the lighter snow flakes which may have not been removed by the centrifugal effect.
The unit easily mounts on both internal focus lenses and external focus lenses with external diameters of 75-105mm. For internal focus lenses the Spintec RD simply snaps on. External focus lenses are mounted via special bracketry which mounts onto standard 15mm rods.
The Spintec RD operates via a 12 volt power supply directly off the camera battery.