The Britool combination spanners (Imperial) 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. ASME B 107-100The Britool BRIE113242B 12 piece combination spanner set includes the following spanners:1/4, 5/16, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8 and 15/16 AF.