Buy direct from THINBIT. RT21BR MICROBIT Uncoated Solid Carbide Reverse Profiling tool, .125" Minimum bore, .375" Reach, Standard Elliptical neck with .052" projection and 1/8" Shank. DURA-MAX 2000 is a versatile and tough sub-micron grain carbide. Because of its high transverse rupture strength and fine grain structure, DURA-MAX 2000 performs well with interrupted cuts. This grade is recommended for cutting steel, cast iron and stainless steel. Kaiser Tool Company, Inc. makes all products in Fort Wayne, Indiana and has over 50 years producing THINBIT products. Our principles are Quality Products, Fast Delivery and Superior Customer Service. Please Note: Final shipping costs will be calculated at checkout based on value of all THINBIT items ordered. THINBIT, MICROBIT and DURA-MAX are registered trademarks exclusively licensed to Kaiser Tool Company, Inc. in the U.S. and/or other countries.