Each pack contains 100 sheets cut to 8.5 x 11 inch standard letter size. It is a fast chromatography paper that is 400 microns thick. This is a good paper for wax printed devices that use capillary transport or where you're storing reagents dried on the paper. However, it's so thick you will need to print wax on both sides of the paper to obtain a reliable seal through the thickness of the paper.