These thru-axles are specific to the Redwood models. Make sure to select the same thru-axle for the model you own as they are specific to the derailleur hanger you have.

Bolt-on style is used with the Allen Key to tighten and loosen the axle. The Bolt-on style thru axle works with the threaded rear derailleur hanger. If you have a derailleur hanger that uses a nut or end-piece to secure the axle then you need to get the Bolt-on style (rear) for non-threaded hanger.

*Note: You can switch to the bolt-on style allen key for threaded hangers simply by purchasing the threaded redwood hanger available here.