DEWALT DW5437B25 1/2 x 4 x 6 Rock Carbide SDS Hammer Bit; For use with electric or cordless rotary hammers, used for drilling holes in poured concrete and other masonry up to 1-1/8" diameter. A ROCK CARBIDE tip maximizes carbide surface contact for longer bit life. The four flute design cleans debris out for fast, efficient drilling. 1/2" Diameter, 4" Usable length, and 6" Overall length. These are sold in bulk packs of 25.