Screwdriver Bit Wera 840/4 Z SB

The Wera 840/4 Z SB screwdriver bit is a precision hex bit designed for accurate fastening tasks. It has a 4 mm hex tip and an overall length of 152 mm, paired with a 1/4" hexagonal shank for compatibility with common bit holders and screwdrivers. Packaged in a blister, this bit is intended for reliable insertion into drivers and offers consistent contact with fasteners in assembly, maintenance, and repair operations.

Advantages

This screwdriver bit combines a precisely machined 4 mm hex tip with a standardized 1/4" hex shank, ensuring good fit and torque transfer to compatible holders. The 152 mm length gives extended reach for recessed or hard-to-access fasteners while maintaining control and stability. The blister packaging protects the bit during storage and transport and keeps it readily accessible.

Suitable for

• Assembly tasks requiring a 4 mm hex driver
• Maintenance and repair of machinery with hex fasteners
• Work in recessed or deep-set screw locations where extra reach is needed
• Use with manual or powered bit drivers that accept 1/4" hex bits

Key specifications

• Tip type: 4 mm hex (Hexagon)
• Total length: 152 mm
• Shank type: 1/4" hexagonal shank
• Package: blister pack for single-bit storage
• Material and finish: high-strength tool steel with durable surface treatment

How to use

Insert the 1/4" hexagonal shank into a compatible bit holder, ratchet adapter, or powered driver. Align the 4 mm hex tip with the fastener head and apply steady axial pressure while turning the driver to engage or release the fastener. Use torque control features on powered drivers where available to avoid over-tightening. After use, return the bit to its blister packaging or a suitable storage system to prevent damage and keep it clean.

Usage recommendations

Choose the Wera 840/4 Z SB for tasks that require a precise 4 mm hex interface and extended reach. Verify compatibility with your driver or holder and avoid excessive lateral force to preserve tip geometry. For high-torque or impact applications, use bits and holders specifically rated for impact use.