The Alvin 110 series mechanical drafting scales are popular draftman scales for schools and vocational use. They are inexpensive rulers made of satin-finished high impact plastic with tapered edges and black easy-to-read printed graduations that won't rub off. The scales are white or yellow with graduations: 1/8, ¼, ½, to the foot; ¼, 3/8, ½, ¾ size; 50ths and 60ths.