Pro-Series 10 Piece SK10 Lyndex Style Straight Shank Collet Chuck Set ~ Runout is less than or equal to 5 Micron. ~ Dual contacts of the taper and flange. ~ Increased spindle contact by 53% over standard holders. ~ Prevents tools from pulling into spindle. ~ Slim design for better clearance. ~ Maximum speed is 15,000 RPM. ~ Shank is 20mm X 100mm overall length. ~ Set includes 1 piece of a straight shank SK10 holder and 8 SK10 collets including 3, 4, 5, 6, 7, 8, 9, & 10mm. ~ Set also includes a wrench and a fitted case.