The product is described by the manufacturer WIHA as a spare part for precise installation and removal of plus/minus screws

as stated in the product text

WP 65 (specified on product page)

The manufacturer's product page has been used as the source for all information in this text

Bit serie 4 unbrako 1/4": SW4,0x50mm MIL4211101401 The product is described byProduct Category: Bit (840 4 Z Hex Plus) The Wera 05059610001 is an 840 4 Z Hex Plus bit with a 4. 0 mm tip and a 50 mm blade length. This product is designed for internal hexagon screws and is listed in WERA's official product list for the 840 4 Z bits series. What the product is and does The bit is a Z (zhhart tough) Hex Plus variant, which in the manufacturer's documentation denotes a hard and universal construction variant. The Hex Plus geometry