Designed to work with most bench vises. Securely holds round shapes from 3/8"(9.525mm) to 2"(50.8mm). Also useful to hold Dremel tools and die grinders for hands free operation. Turn your hand grinder into a bench grinder. Made in the USA from hand-poured semi-soft polyurethane. Powerful neodymium magnets hold the v-blocks to a vise. Dimensions are the following: Length: 4.0" (102mm), Width: 1.5" (38mm), Height: 2.0" (51mm). Available in a variety of colors on special request. Contact us for details.