An adjustable spanner cut for AN fittings, which is a different proposition to an ordinary adjustable. The jaws are shaped and spaced for the shallow hex flats used on AN hose ends and adapters, so they grip the full flat rather than the corners, and the material is chosen to be kinder to anodising than hardened steel. That means one tool covers several fitting sizes without rounding them off. It suits a mobile toolkit or an occasional builder who does not need a full spanner set. For assembly work on a big system, a fixed set is still faster, but this handles the odd size you did not budget for.