Flat round piece of natural calfskin. Thin = approximately 0.01 of an inch or 3-4 sheets of printer paper Medium = approximately 0.015 of an inch or 4-5 sheets of printer paper Thick = approximately 0.02 of an inch or 5-6 sheets of printer paper All skins sold AS IS . We do our best to eliminate skins that have possible defects; however our prices are based on an as is basis. This means on average you can expect to lose one out of ten skins. Obviously the tightness during installation will alter this ratio so figure this loss in your cost.