Melco No.9 Metric Box Spanner Set 8 Piece 8-22mmBox spanners are thinner than a socket and are much longer so that they can be used to loosen or tighten bolts and nuts in narrow recesses, meaning that they are often used in plumbing maintenance and automotive repair. These Melco tubular box spanners are made from bright plated steel and able to accommodate a tommy bar. The 8 piece set comprises: 8 x 9 mm x 3. 1 4in Long (82mm) Double ended 10 mm x 2in Long (50mm) Single ended 11 mm x 2in Long