Wondered if you meant those series filters, and doing a quick search I see you asked on APUG - apparently that's what it refers to. Seems like they were pretty common and not particularly valuable.
I have some, the lower numbers were for earlier cameras with smaller lenses; by Series VI and VII they were sized to fit midcentury cameras. You just pop 'em on and off (edit-using the retaining ring depending on the camera), many were in orange or yellow etc. to use with B&W film I think.