The Surly Tuggnut is a stainless-steel chain tensioner designed to keep rear wheels securely in place in rear-facing horizontal dropouts, including Surly frames. Its investment-cast body ensures strength and durability, while the thumbscrew and dual axle holes offer a wide range of fore/aft adjustment. Includes an aluminum adapter sleeve for compatibility with both 10mm nutted and 6mm quick-release axles. Also features a built-in bottle opener.