The MK-303 Professional 4" diamond blade is a continuous rim blade for lapidary materials. (Details: diameter-4" or 102mm; rim width - .020; arbor - 5/8"; part #153689). It produces smoother cuts and is used for cutting rare and valuable materials when waste must be held to a minimum and speed of cut is essential. The Professional series diamond blades last longer and will cut faster than ordinary notched-rim or plated diamond blades. Made in the U.S.A. Price is listed retail and a 20% discount will be applied at the SHOPPING CART. Made in the U.S.A. FOB Torrance, CA or Powell, WY.