Inverted Rubbers or normal pimple in rubbers vary in speed, tackiness, spin to give you the dynamic game play you need in your style of play. Fast, tacky spin rubbers for an offensive game or anti spin slower rubbers for a defensive game. And all-round for anything in-between. Thicknesses vary from 1.3mm to 2.3mm, the thicker the faster. Rubbers also come in varying softness from hard to medium to soft. Softer rubbers offer more control and deeper feel of the ball.