[Roadsters] Source for window U-channel liner?

[J Sandhoff]

Anyone have a source for the U-channel felt that the windows slide in?
This is the material that lines the steel window guides inside the
doors. A heavy rubber-like U-shape material that's covered in tough
felt-like fabric.

Thanks for any leads,

-- John
    John F Sandhoff   jsandhoff at gmail.com   Sacramento, CA