Champion CSK-SET-4 Zero Flute 82-Degree Countersink Set, 4-Piece Chatter less finish Single cutting edge for fast stock removal and free-cutting. Easily sharpened by using a small mounted grinding wheel inserted in the hole. Ideal for use in portable applications and materials, including metal, plastic and wood, especially in the glass and window design industry. Contents include 82 Degree pilotless/round CSK6S, CSK8S, CSK10S, CSK18 and case.