These Super bits received the "Best Overall" rating by Fine Woodworking Magazine in 2008 The Super bit features the traditional design with a circular rim, double cutters and a finely ground center point. These bits will produce a flat bottom hole with smooth sides in both soft and hard woods, veneers, MDF or any panel material. Guided by its circular rim, the bit will cut cleanly without deflection by grain or knots. A new patented cutter geometry makes for less friction, better cutting performance and an extended service life. A new groove design makes a better chip flow and clearance. The bit is a machined from high carbon alloy tool steel with typical German attention to detail and precision. Overall the bit length is 3 1/2" with a 5/16 shank for bits 1/4" to 13/16" and a 3/8" shank for bits 7/8" to 2 1/8". Made in Germany.