The Britool combination spanners (metric) are crafted in chrome vanadium steel and finished in high chrome. The ring spanner end has a 12-point OGV profile angled at 15 , maximising the contact surface with the nut for a longer lifetime. The open end is angled at 15 from the handle axis. ISO 691 - ISO 1711-1 - ISO 3318 - ISO 7738 - DIN 3113.