THIS IS A PROCUNIER MODEL 1E HIGH-SPEED TAPPING ATTACHMENT FEATURING A 3MT SHANK. IT IS CLASSIFIED AS AN E SERIES/STYLE, HIGH SPEED, LIGHTWEIGHT, EXTRA SENSITIVE TAPPER. THIS ATTACHMENT IS RATED FOR A MAXIMUM SPEED OF 3,000 RPM. TAPPING CAPACITY IN STEEL RANGES FROM #0 TO #10, AND CAPACITY IN SOFT MATERIALS RANGES FROM #0 TO 1/4".