These AF, imperial combination spanners are forged in chrome vanadium steel and have a high chrome finish. 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.