Historical
ISO 2725-1:2007
Assembly tools for screws and nuts - Square drive sockets - Part 1: Hand-operated sockets
ISO 2725-1:2007 specifies dimensions, the designation and the marking of hand-operated square drive sockets with operating end and having a hexagonal or double hexagonal form in accordance with ISO 1174-1.
Machine-operated sockets (#8220;impact#8221;) are dealt with in ISO 2725-2.
International Organization for Standardization [iso]