Key Features:Material: premium flex plus carbon steelSurface finish: chrome plated according to ISO 1456:2009The dimension of the hexagonal key opening is SW10. It enables unscrewing and tightening of nuts of this dimension, while at the same time it can be used to hang the key.How to use the tool:The wrench is used for unscrewing and tightening of front chain ring nuts. The tightening starts with the broader part, and when the nut is sufficiently tightened, it finishes with the narrower part which is bent in order to enable more secure power transfer during the final tightening of the nut. When unscrewing the nut, the key is used in the reverse order.