XccMe Iced Coffee Silicone Ring for Cold Beverages,Reusable Silicone Lid for 30oz Stainless Steel Tumbler,for YETI,RTIC,BJPKPK,for The Cup Mouth Diameter 3.9-4 inch (Black)

This is the best addition to a cup that I already have, this helps my drinks that I buy anywhere to fit well and stay cold all day. Will not promise leak proof but it’s works amazing to keep your drinks cold. Super easy to put on the top of your metal cup and then just put the new coffee cup inside.

Fit onto 30oz yeti tumbler perfectly. Worked for a Dunkin medium & a McDonald's large mcafe so far. Much better option for someone who already has a lot of tumblers/prefers a specific type, & price was great.

I've been pouring my drinks from the fast food cups into my Stanley... always a messy experience. Someone else who found themselves doing the same thing decided to do something about it. This little device is so simple but so smart. It fits perfectly on the lip of my cup and allows me to slip my plastic drink cup into the Stanley. It holds the plastic cup and keeps it from banging around inside the Stanley. This is one of those inexpensive little things that can make your life a little more efficient.

Lost my other one. Ordered to keep my coffees cold I order from Starbucks.