SURLY Single-Speed Kit - Spacers and LockringSurly Single Speed Spacer Kit comes with a selection of anodized aluminum spacers, so you can get a perfect chainline to complement your road, track or mountain crankset. Our large diameter, stainless steel Cassette Lockring holds everything together and perfectly matches the outside diameter of the spacers. Plus, it matches the machined shoulder of our single speed cassette cogs (not included). The lockring is machined to utilize a common Shimano