Info from Manufacturer: 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.