Greyhound Auto Retail stocks spanners and spanner sets for automotive and workshop use, including ring, open-end, combination and ratchet ring types in metric sizes.Each end has a purpose. A ring spanner surrounds the fastener and grips all six flats, so it is the one to use wherever access allows, particularly on tight or corroded nuts. An open-end is for situations where the spanner has to slide in sideways onto the flats, but it grips only two faces and is far more likely to round a stubborn fastener. Ratchet ring spanners combine the grip of a ring with the speed of a ratchet and are excellent in confined engine bay work.Buy sets in chrome vanadium steel with a proper heat treatment. A cheap spanner that spreads under load damages the fastener as well as itself.