Wayne's Audio Turntable Periphery Stabilizing Outer Ring

I bought one, used, perfect, nice price compared to new at Wayne's. SS-1 or SS-2, it's downstairs,

https://www.waynesaudio.com/shop

I'm using a walker these days, I'll find which one another time.

It's very nice, impressive quality, has easy centering device. I intended to use it for all LP's, not just warped ones, more stable contact with mat, combined with center weight I use now. Basically, let the stylus move, not the grooves.

Even new 180 g LP's have minor warps I find.

Unfortunately, the weights that hang down just hit the wide rim of my Vintage JVC TT, TT81

http://www.thevintageknob.org/jvc-TT-81.html

So, I'm gonna part with it, just been distracted by medical issues the past 5 months.

All very informative responses, thank you all. Unfortunately there’s no OEM ring for Technics, so either I machine one or 3rd party tweek like Wayne’s … he does have one specifically for Technics which does not employ the hanging weights as the platter perimeter is chamfered. The PITA factor may very well determine how much of a role one of these plays in my listening.

I tried one of these a few years back. the centering hold is not precise enough to ensure an accurate placement of the ring. Secondly the mass was really not high enough on the one I bought to feel it did the job properly. I returned mine, did not feel it really was doing the job correctly. 

I use an old TTW ring on my VPI with the original acrylic-lead platter that is too small for the VPI ring. 

My ring is about 2.5 pounds.  I find that to be sufficient.  Not only does it flatten records, but it bonds all records to the platter.  Beyond that it adds weight to the platter beyond the platter itself adding to the flywheel effect and benefiting speed stability.

IMO it benefits the SQ of all recordings and I wouldn't be without one.  It is also far easier for me to place on a disk than a screw in VPI center weight, as those need adjustment for particular records. I do use a "dead" center weight.  It has all become quicker and more automatic for me than the screw in weight.

It is true these rings can ruin a stylus.  Of course one can be very careful.  My own response was to make the placement of  the stylus at the beginning of a record so automatic and precise that I can do it blindfolded.  I wrote that up here on another site.  It's been many years and it has never failed.

@melm the O-ring is a great idea!