Those blades can be used in other razors.
I believe the Feather blades were originally made for the Valet Autostrop, or at least the Feather version. I have only seen one posted on B&B, but they do exist.
I am hosting a OneBlade pass-around elsewhere. When it winds down I may flip it over to B&B so that others can experience the razor. It has practically ruined me as I find it so incredibly smooth, and it provides my face with the best shaves of a lifetime.