0.40mm 2FL Square 3XD Multi-Purpose Micro Carbide End Mill, 1.20mm LOC, 3mm Shank, 38mm OAL, AT - AlTiN Coated 1.20mm LOC,3mm Shank,38mm OAL MPL Series: Multi-Purpose decimal micro end mills 3 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 #40116AT