Cloth area is 7.25″ x 4″. Each card weighs around 9 ounces, it varies depending on the density of the piece of wood used.
The 72 psi are good for coarse to medium wools. The 108 psi are good for medium to fine wools like merino and corriedale, angoro, alpaca, llama, blending pet fur ect. If you like to work with a variety of fiber we recommend the 108 as you will get better prepared fiber. If you mainly work with a few medium breed wools, then the 72 will work faster and with less effort.