The Surly Excellent Adventure Thru-Axle is a 12mm bolt-on thru-axle designed for hauling Surly's Bill and Ted cargo trailers with your bike. If your bicycle is equipped with a boost 148, 12mm thru-axle hub and you feel compelled to haul cargo, your Excellent Adventure awaits. 12 x 148mm hub compatibility only Designed for use only with Surly's Bill and Ted Trailers Works with slotted horizontal or vertical single-position dropouts Compatible models: Karate Monkey, Krampus, Grappler, Ogre, Lowside, ECR, Troll, and Skid Loader Specifications Axle Diameter (mm)12ColorBlackRear Axle Type12mm Thru x 148mm