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 5 / 8 x 11 / 16 Whitworth Double Ended Length: 6in 150mm.