Wera 840/1 ZBO Hex Pinned Security Bit Extra Tough 4mm 25mm Pack of 1

This Wera 840/1 ZBO bit is supplied in a 4mm hex size with a 25mm length, a highly practical size for medium-format hexagon socket BO security screws commonly encountered in plant equipment, fabrication work, and mechanical assemblies. The 4mm drive provides a firm, positive engagement with tamper-proof fixings that standard hex tools cannot shift. Wera's Hex-Plus profile delivers a greater contact surface within the screw head, greatly reducing the chance of cam-out or rounding — a common issue with conventional hex bits. The extra tough specification ensures this bit performs consistently even when working with harder materials or under sustained torque.