With the Tacx 142×12 mm E-Thru Turbo Trainer Axle you use an axle skewer to put your mountain bike on a Tacx trainer. These axles are only suitable for the Tacx classic trainers. Separate axles are available for direct drive trainers, & replace the standard axle skewer. The Tacx E-Thru trainer axle M12x 1, with metric fine thread is suitable for hubs with axle skewer attachment 142×12 mm: various DT Swiss & Shimano types.