0.55mm 4FL Square 1.5XD Multi-Purpose Micro Carbide End Mill, .83mm LOC, 3mm Shank, 38mm OAL, D1 - PVD Diamond Coated .83mm LOC,3mm Shank,38mm OAL MP Series: Multi-Purpose decimal micro end mills 1.5 x diameter length of cut. Premium carbide substrate with advanced geometry for diverse application range. Use uncoated for general purpose materials. Use AT in cobalt chrome, steels, stainless, high-temp alloys, and more. Use D1 PVD Diamond in graphites, aluminum silicon alloys, carbon fiber composites, reinforced plastics, & more. Round Tool Laboratories USA Part #40810D1