I have multiple brands of tumblers, these fit the Yeti, Ozark, and OuterEQ just fine. I have only used these with iced drinks so far. My only complaint is they make a whistling sound when you drink out of them. I also have the magnetic Yeti version of these lids and they do not make that noise and seem to be "heavier" duty, but I can get 2 of these lids for the price of one of those.....

Bought as replacement for my RTIC. While the cup itself has survived unscathed after various road adventures and accidents, the plastic tops unfortunately do not. I bought this one however for the utility. I typically use my RTIC for water and use a SS straw. This lid allowed for both that and for a closing lid should I choose to serve up coffee one morning instead.

The kid I got with my insulated cup had become loose in a very short time. If I held the handle with my thumb on the lip of the lid I was in danger of flipping the cup open. It happened twice and both times made a mess so I was in need of a replacement lid. I bought this two pack and couldn't be happier. They fit perfectly and considerably tighter than the lid that came with the cup. If you want this lid to come off you have to mean it!

If you're like me and don't like the thickness of the lip part of a Yeti and RTIC cup lid, then this lid isn't going to be an improvement over those. They are basically the same lid, but with a slider that reduces spillage, but does not stop it. Also, the slider sometimes slips a little and touches my lip when I'm trying to get a drink and this bothers me. When it slips, it makes a whistle sound while I drink, another annoyance.
Why did I give it 3 stars? It fits the cup well and does stop some of the spillage which helps to keep the messes smaller. (I'm clumsy.) Despite the issues, I do prefer it to the lid that came with the cup.

Two stars because technically, these can be called spill resistant, and they fit the 30 oz. Yeti tumblers very well. I saw mixed reviews on the slider piece before I ordered, so I want to verify very clearly--the slider has NO built in resistance, like a tab or bump to stop it, so it moves the direction the cup is tipped. When you tip the cup up to drink out of it, the slider slips over the hole. With a smaller cup, you could hold the slider open with one hand as you tip the cup up, but with these ginormous 30 oz. cups, I can barely grip them in one hand and could definitely not keep the slider open while taking a drink unless I used two hands. I was looking for a lid to offer some protection in the event that the cup tips over, and these will NOT work for that purpose. I guess if you needed a lid to minimize splashing when moving around, etc. these might work, but I can't recommend them. I returned mine immediately. The product does seem well made and sturdy.