I had this Gibson mini humbucker installed by the fine folks at Black Rider Guitars. The plastic ring is actually from GFS, which was a little easier to install and a better match color-wise with the plastic cover of the P90 in the neck position. The Gibson ring is more of a light brown or tan compared to the cream color you see here. The GFS ring
looks perfect to me; a big thumbs up to that little piece of hardware.
Unfortunately everyone in the house is sick, including me, so I won't be cranking it up through an amp until we're all better. So the sonic qualities haven't been fully explored yet.