The Tacx Trainer Axle for E-thru M12x1 allows you to put your mountain bike in the Tacx® trainer. Axles are only compatible with Tacx classic trainers. Separate axles are available for direct drive trainers, and they replace the standard axle skewer.E-Thru trainer axle M12x1, with metric fine thread - suitable for hubs with axle skewer attachment 142 ×12 mm: DT Swiss RWS axle skewer (conical and flat), Syntace X-12 system (Specialized) and various Shimano types.