Cyclone HSS Premium Grade Annular Cutter, 13 16 in dia x 1 in Depth, 3 4 in Weldon Shank, Includes Pilot Pin ORS NASCO Compact case New high visibility blade Compact case New high visibility blade color & large read numbers Wider blade for added stand out Printing on both sides of blade Precision tools made of rust proof aluminum and anodized for lasting protection The arms are precisely aligned with spring tension joints to guarantee accuracy and rigidity The holder accommodates flat or round soapstone and pencils All are a folding type design Evolution standard geometry is sufficient for most drilling applications Manufactured specifically to maximize hole accuracy while minimizing cutter vibration and extending annular cutter life Using this standard geometry enhances accuracy and saves time This allows for a single ejection of slugs when drilling through stacked material