Melco Ta 18 A/F Box Spanner 7/8 X 1 X 6 in. Box spanners are thinner than a socket & are much longer so that they can be used to loosen or tighten bolts & nuts in narrow recesses, meaning that they are often used in plumbing maintenance & automotive repair. This tubular box spanner is made from bright plated steel & able to accommodate a tommy bar. Size 7/8 x 1 in. AF Double Ended. Length: 6 in. 150 mm.