Jonathan H.wrote a review of RockyMounts MonoRail Single Bike Add-On on August 30, 2018
Familiarity: I've used it several times
This piece adds versatility to the standard 2" Monorail rack. We do not always need to haul 3 bikes on the back of the car so it is only installed when the need arises. It takes less than 2 or 3 minutes to remove the rear cap, slide this in, install to retaining bolts, and reinstall the cap. Not something you want to do every day but to do it once every week or two is not an issue. Or you can just leave it on. And once it is installed it is sturdy without any extra wobble. We are also thinking of getting a single Monorail for our car and this can be used with that too. Definitely recommend if you are considering it.