A Headcote Smart-Bit makes it easy to drill and countersink screw heads at the perfect depth. Its integral stop collar is permanently mounted to the shaft of a four-flute countersink, and its long-life high speed steel drill bit is fixed at the correct pilot hole depth when used in 5/4" thick decking. Allow one Smart-Bit per 100 – 125 square feet of decking (5/4 x 6" on 16" centers). The ball detent style bit fits standard quick-change chucks. Replacement drill bits sold in packs of 5. Made in Taiwan.