Spanner is designed with two different sizes on each end. The 18-21mm end is suitable for 18mm and 21mm nuts and bolts, while the 23mm end is designed for nuts and bolts with that size., Taparia is known for producing high-quality tools, and the 18-21X23 Ring Spanner is no exception., Taparia 18-21X23 Ring Spanner is a versatile tool suitable for various applications. It can be used in automotive repairs, mechanical engineering, construction, and other tasks