The Britool open-end spanners (imperial) are forged in chrome vanadium steel with a high chrome finish. The open end is angled at 15° from the handle axis.

ASME B 107-100.

The Britool BRIE113291B Open end spanner has the following dimensions:
Size: 3/8 x 7/16 AF
Length: 156mm
Weight: 49g
Height: 4.60mm