A quick-release adapter is included with the FollowMe set, which is suitable for bikes with a derailleur. The XL quick release can be used if it is too short. Check here how the difference is measured.

The axle nut adapters replace the rear wheel axle nuts of the parent bike, available in 4 sizes. Sometimes the nuts fall into the frame of the bicycle. These adapters may extend a maximum of 12.5mm into the frame to attach the FollowMe Tandem.

M10 x 1 Inner size of axle nut 9mm:
Is for bikes: Rohloff with fixed axle, backpedal brake without gears, derailleur with fixed axle nuts, NuVinci and Enviolo hub, Sram I motion or Go SwissDrive.

3/8 inch Inner size of axle nut 8.5mm: 
Is for bikes with Shimano Nexus 4, 7 or 8 gears or Alfine 8 or 11 gears.

M12 x 1 Inner size of axle nut 11mm: 
Ion E-bike with rear wheel motor

M12 x 1.25 Inner size of axle nut 10.8mm: 
Rarely occurs. For Ahooga bikes and Decathlon e-bikes (Riverside rear wheel motor)

M6 SRAM Inner size of axle nut 4,4mm: 
Specifically for a few Sram models

A clickbox adapter is required on “granny bikes” and bikes that have a hub gear with a “block” on the right side of the wheel such as: Nexus 3, Sram S7, Sram P5.

Finally, there are bikes with a fixed thru-axle, these are mainly e-bikes. For an overview of all fixed thru-axle adapters and how to measure them, see this PDF document