10PCS Tumbler Shields for Epoxy Tumbler, Silicone Tumbler Protector for Resin Paint,Cup Silicone Insert Paint Spray Shield, Epoxy Resin Cup Protector Clean Rims DIY Glitter Epoxy Tumblers (10)

I get what the purpose is supposed to be to keep the edge clean. I had no success with my 20 oz skinny tumblers. They are too loose and they move around. So I'll continue to use my tapes.

works great, keeps epoxy from overrunning into the inside of cup

The biggest size is a tad bit big for the 30 oz cups but other than that, they have all been great to have!

Got these in hopes they would work like advertised of which none of the sizes properly fit any of the size tumblers and they do not stay in place while working on a cup. It is not worth the money or the fight just for them still not to work in the end. Would not recommend on buying due to these issues.

These rings did not fit tightly inside the cups and resign still ran inside the tumbler and had to be cleaned.

Now this has been a life changer for me. I used to have epoxy and paint within the cups while working on them and gave me a hard time to clean and scrape it off. With these shields I have had 0 difficulty and I love it.

These seem good in theory, but I found that they really didn't fit well even with the numerous size options. They didn't stay put on the cup turner either, eventually working their way off and ruining the product. So much easier to tape or cut excess off with a knife.

Love the sizes helps with less clean up, I'm a little messy with epoxy and this helped with my rims.