The Ketchum Model 201R tattooer uses an 8mm (5/16") size character. This size is great for sheep and cattle. The 201R tattooer features the special Ketchum chisel point pin, which gives illusion of continuous line character. The Model 201R has revolving head with up to 4 characters on each of the two faces of the head. The revolving head quickly spins by pressing in the black octagon tab.