Wayne's Audio Turntable Periphery Stabilizing Outer Ring

FWIW my VPI turntable came with a periphery ring and I have yet to use it. I am nervous about my cartridge getting accidentally hung up on it by my inattention. I run a fairly expensive cartridge so I will live with any warped albums. Luckily so far I do not have any bad warped albums. The worst one I sent back for a refund. 

You might try to borrow one before purchasing if it is an option.

I have the VPI periphery ring and use it on a few warped records that NEED it. It works perfectly but on the average record I don't use it.

I had a TT weights ring many yrs back and while it worked it was a PITA to use. Had yo use a centering contraption to make sure it was on perfect then had to be VERY careful with your cartridge not to get damaged. Used it for a month then it sat unused. Not worth the hassle. Prefer a screw down record clamp now.

I have one. It made a huge difference. Cupped albums are now dead flat. The sonic differences are noticeable. Worth every penny.