United Abrasives- SAIT 45011 Tungsten Carbide Die Grinder Bur SD3 Double Cut/Alternate Cut 3/8" x 5/16" x 1/4" Tungsten Carbide construcion for long life and durability High Quality Manufacturing method delivers vibratin free operation Precision ground with diamond wheels to produce a very sharp uniform cutting edge Each enclosed in individual plastic capsules for storage and protection Excellent for confined or hard to reach areas