To undo the through axles on your disc bike, you need a 6mm hex key. You could stuff that in you pocket. But it might be better to attach it to the through axle.

This switchlever attaches to the 6mm hex of your through axle, but can be taken out, and switched to you other axle. Hence the name.

The switchlever is a standard 6mm hex key, can be used for other goals than through axles. It doesn’t mount to every through axle, you need Raamwerk Through Axles to have a secure fit while riding.

One is included in the Road Race Disc Frameset or Complete bike