The NO4 C-slotted Impact Driver Bit is a single flat-blade screwdriver bit designed for use with impact drivers and quick-change 1/4" hex chucks. Its primary use is to drive slotted (flat-head) screws where impact action is required, for example to loosen seized fasteners or to rapidly drive screws in timber, metal and plastics without risking bit breakage from shock loads.

This bit is manufactured from S2 tool steel and is heat-treated to give a tip hardness in the typical range for impact bits (approximately HRC 58–62), providing the toughness needed to resist fracture under repeated impact. The shank is produced to DIN 3126 / ISO 1173 1/4" hex dimensions for reliable fitment in standard impact-driver chucks. The tip is a No.4 slotted (C-slot) profile, machined to accurate tolerances for secure seating in slotted screw heads and to minimise cam‑out. The finished surface is black phosphate/black oxide coated to give enhanced corrosion resistance and reduced glare during use.

Typical applications include maintenance and repair work, joinery and carpentry, electrical installation, plumbing and HVAC fitting, and field service work in light engineering and agriculture. The bit is suitable where higher torque or impact is needed to free rusted or over-tightened screws that would damage a conventional screwdriver bit. It is also used by tradespeople who require a robust slotted tip for one‑off adjustments or demolition work.

Key benefits of the NO4 C-slotted Impact Driver Bit are its impact‑rated S2 construction for improved fracture resistance compared with standard chrome vanadium bits, the corrosion protection from the black phosphate finish, and the standard 1/4" hex shank for wide compatibility with modern cordless impact drivers and bit holders. The accurately formed No.4 slot reduces stripping of screw heads and improves transfer of torque.

Duchy Fasteners stocks this Draper Tools Group D item (DR10820) individually and in multi‑pack options; other slotted sizes and complementary Draper impact bit types are also available to cover a full range of fastener sizes and applications.