3-Flat Secure-Grip shank holds the bit firmly in the chuck for reduced slipping. Reinforced flute geometry increases bit stability for faster drilling. Carbide tips extend performance in masonry applications. 3-Flat Secure-Grip shank fits in all 1/2" three-jaw hammer-drill chucks and maintains unyielding bit hold with heavy torsional loads. Designed especially for conical anchor, concrete screw, nail-in and hollow wall anchor applications. Set includes 1 each: 5/32", 5/16", 3/8", 3/16", 1/4" in 6" lengths.