Racket grips are either
replacement grips or
overgrips. Knowing the difference between them is essential. Replacement grips usually come pre-installed over the handle of the rackets and don't need to be replaced often; they have a sticky backing and offer a reasonable amount of cushioning. Overgrips, on the other hand, don't usually have a sticky backing and are much thinner. Overgips are used on top of the replacement grip to provide specific gripping characteristics or to slightly increase the grip size of a racket. They commonly offer one or more of these characteristics: tacky surface to provide extra grip, absorbency for sweat and textured surfaces for extra grip.