Weiler® Tiger® Zirc 1-1/2 x 3 in type 18r plugs are designed to deliver exceptional durability and a fast cut rate for performance you can count on. Our advanced bond technology provides long product life while sharp and durable zirconia abrasive grains cut smoothly and hold up in the most challenging foundry cleaning room applications. The type 18r shape features a rounded cutting surface that is ideal for id cleaning, hole edge beveling, smoothing weld seams, removing gates and parting lines and cleaning castings in hard-to-reach places. These plugs offer a 5/8-11 in arbor and are designed for use on straight grinders and die grinders. Tiger® Zirc Grinding Plug, Portable, 1-1/2 in Diameter Maximum, 3 in Head Thickness, 20 Grit, ZA20S Grade, 5/8-11 Center Hole, Synthetic Resin Bond, Type 18R/Round Tip Shape, 5/8-11 UNC Thread, 24190 RPM Maximum, Zirconia Alumina Abrasive