The Pilot Hole Punch makes starter holes for brass brads at electrical interconnection points. The diameter of the punching tip is smaller than the smallest brad used, thus reducing the risk of punching excessively large holes in the copper foil tape runs.
The locking chuck provides an easy method of needle replacement (two needles included) in the event of breakage. Overall length is 4-13/16" with a handle diameter of 3/8".