Tennis overgrips are designed as a temporary solution to wrap over your base racquet grip for short-term assistance with a slipping grip.  They need to be removed and re-applied with some frequency as they wear, which is why they are often sold in multi-packs.  Overgrips are categorized as either tacky or dry feeling.  Many players know dry feeling overgrips as the original Tourna Grip (blue overgrip) made well-known by Pete Sampras in the past and still used by many pro players on tour.  These are constructed of a sueded or fabric-feeling, sweat absorbing material. Tacky overgrips tend to have a more rubbery, sticky feel.  When wrapped properly, tennis overgrips add about 1/16" of size to the racquet grip size.
