The topsheet of the Rasanter rubbers has a high degree of glossiness to compensate for the loss of rotation after the introduction of plastic ball. R is for rotation. These rubbers have better spin potential and allow you to consistently play a large variety of shots. Rasanter R37 is by far the softest and most controllable of the rubber series. The soft sponge brings about a high degree of dwell time to allow a player to block, push, and loop with proper placement. This rubber is a reasonable choice for lower level player developing their stokes or even for top level allround player with a strong preference for soft rubbers.