The spanners have a 12-point OGV ratcheting ring end which is flexible through 180 degrees, and provides 5 increments. The OGV profile maximises the contact space with the nut for a longer lifetime. The direction is switched by turning the wrench. The open end is angled at 15 degrees from the handle axis (increment angle 30 degrees). Forged from Chrome Vanadium steel with a high chrome finish. ISO 691 - ISO 1711-1. Contents: 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19mm.