Vintage correct "Country Gent" style clear plastic trim rings, may be back-painted with paint to match your guitar.
These are Pickup mounting rings- the pickup will mount to the adapter bar, which then hangs underneath this pickup ring.
These are vintage correct and fit any correct spec Filter'Tron pickups including our GFS GF'Tron pickups. These use the vintage spec sizing, 50mmx95mm, with the four holes spaced at 83mm wide by 34.25 mm high. The holes for the pickup height adjust screws are at 78mm across.