This is a NO4 Pozi‑type impact driver bit designed for use with impact drivers and power screwdrivers to drive Pozidriv (PZ) screws of the larger PZ4 size. Its primary use is to deliver repeated percussive torque into Pozidriv fasteners for heavy assembly and structural fastening where standard screwdriver bits would wear or cam‑out.

The bit is manufactured from S2 tool steel and heat‑treated to achieve a hardness in the region of 58–62 HRC for long life under impact loading. It is supplied with a matt black phosphate finish to give a degree of corrosion resistance and to reduce fretting between bit and holder. The shank is a 1/4" (6.35 mm) hex, conforming to common 1/4" hex driver interfaces (DIN 3126 Type E6.3 compatible), so it fits directly into most quick‑change chucks, bit holders and impact driver collets. The tip is formed to the Pozidriv profile (PZ4), sized to match BS/DIN/ISO Pozidriv screw geometries for positive engagement and reduced cam‑out compared with equivalent Phillips profiles.

Typical applications include heavy timber work, decking, sub‑flooring, joinery and construction where larger Pozidriv screws are specified. It is also used by installers fitting large cabinets and fixtures, by maintenance engineers and in industrial assembly where higher torque and repetitive driving are required. The impact‑specific heat treatment and geometry make the bit especially suitable for high‑cycle professional use in trade and contractor environments.

Key benefits are improved durability under impact use thanks to S2 construction and heat treatment, corrosion resistance from the black phosphate finish, and reliable screw engagement through the PZ4 profile which reduces stripping and cam‑out. The 1/4" hex shank ensures broad compatibility with standard bit holders and quick‑change systems, allowing rapid tool changes on site.

Duchy Fasteners stocks this NO4 Pozi impact bit in individual pieces and in multipacks, with common lengths and pack sizes available to suit site and workshop needs. Please contact Duchy Fasteners for current size and pack options.