At least that is what they are called in the JC Whitney catalog.
I have put them on several cars. Believe it or not, they attach with double sided tape.
They are specifically made for particular car models. You can't just order one for a
Boler door. You'd have to have your dimensions in mind and when you see a car with the approximate correct ones, remember the model of car to order them.
To the best of my knowledge they don't sell them as say...for 28"
windows, they sell them by car model.
They are nice though, and it is a really good idea.