Combination Spanner (20mm)

If that is the situation, the first thing to do is confirm the size rather than guess it. Fastener heads are not marked, and 19, 20, 21 and 22 are close enough that eye judgement is unreliable, particularly on a head that is rusty or slightly rounded already. Measure across the flats, from one face to the face directly opposite, not corner to corner. A vernier or digital caliper does it in seconds and we stock both. If you have no caliper, take the fastener or a photograph with a rule beside it to a counter and let somebody measure it.

That two minute check is worth making, because the alternative is buying the nearest size and trying it, and the nearest size is what rounds fasteners. A spanner that is a millimetre oversize contacts only the corners of the head, and on a fixing already tight enough to need a new tool, those corners will not survive the attempt.

Twenty millimetre heads turn up on imported machinery and plant, on hydraulic and pneumatic assemblies, on pumps, compressors and generators, on agricultural equipment, and on heavy vehicle components. It is a size that belongs to particular equipment rather than to general work, which is exactly why sets leave it out.

Forged carbon steel, hardened and tempered, satin matt chrome plated for corrosion protection.

Buyers are machinery and plant fitters, hydraulic engineers, generator and pump servicing, agricultural and heavy vehicle workshops, and industrial hardware dealers who stock the sizes ordinary shops do not.

Send us the measurement on 94 77 111 8880 and we will confirm the size before you buy rather than after. Delivered anywhere in the island.