Destined to become a Classic! The Park Tools SW-22 Red 3.5mm Master Spoke Wrench is an investment cash workhorse poured from the best steel, precisely machined, heat treated for hardness, then polished and plated. The result is a smooth, solid steel spoke wrench designed and built to fit perfectly in your hand and provide years of every day service. The SW-22 Red 3.5 master spoke wrench is a four sided wrench to grab the four corners of the square nipples. The Park Tools SW-22 Red 3.5mm Master Spoke Wrench SW-22 is sized for .136" (3.45mm) nipples.