1/4" drive Phillips bits with a hole drilled in the tip for use on screws with a security pin. Phillips Pinheads are found in some electronics, including Apple G5 power supplies, these bits are available in #1, #2, and #3 sizes, corresponding to the same sizes as standard Phillips bits.
Note: This bit doesn't include a driver. These will fit all standard 1/4" driver handles and bit holders.
The pinhead fastener is not designed for high torque, and neither is the bit. It is a low torque security application only. The engineering of a Phillips bit with a hole in the middle makes for a rather weak design. These bits can break if used to over tighten a fastener.