O-Sip! Silicone Sippy Lids (Pack of 3) - Spill-Proof Fun for Families! - BPA-Free, Fits on Glasses, Mason Jars & Cups - Reusable, Durable, & Kid-Friendly (Colors: Red, Green, Blue) - ModFamily

It took me a while to get used to these. They are mostly leakproof, but I wouldn't put them on a cup with fluid and toss it in a bag. And my almost 2 year old likes to bang it upside down on her tray at dinner which does cause milk to come out. But, for the most part they have replaced sippy cups in our house. The eventual goal was to use them with small aluminum cups and get rid of our plastic cups, but for now I'm satisfied with how easy they are to use and clean.

Brilliant idea...but it needs some tweaking. These are good lids for a child who doesn't drop or throw their cup - that is to say, who doesn't need a sippy lid to begin with. Yes, they're leak proof if you carefully hold them upside down. They're not leak proof when they're upside down on the ground with the floor pressing against the soft silicone. They're not leak proof if your child holds them upside down and squeezes them. They're not leak proof once your little one discovers that the holes are stretchy and they can stick their finger all the way in...and then the hole rips. They really do stretch to fit almost any cup, and the grip and seal is great. They never leak from the sides. Also, they're very easy to clean. I think if someone modified these with a hard flat top, where you can put a regular mouthpiece with a valve, and then silicone around the sides so they can still fit a variety of cups, that would be perfect.

[Updated 01 March 2017] Look I'm gonna be honest. I'm an adult and I use these for myself. Having a chronic pain condition leaves me in bed more days than not, and the way our studio is set up we don't have space for a flat surface near the bed. I've tried a tonne of supposedly "spill proof" adult cups and I am just... too clumsy and they're not totally negligent / butterfingers proof. So I got these, feeling really embarrassed. But you know what? They work. The liquid is only released if overfilled (via the ventilation hole in the middle) or, as is meant to be, when the spout portion is squeezed. I have a lot of cups and tumblers that I thought would be useless since the lids aren't leak proof now seeing plenty of use with these lids. I've had these since November of 2017 and it is now March of 2017 and I haven't had a single issue -- no rips, no spills, no wear and tear. I saw a review earlier that commented on ripping on standard kid-sized cups within two months but I haven't had that experience; they are, however, difficult to put on (esp with chronic pain issues, I have to get my fiance to put them on for me) and you have to be careful not to overstretch them. You may also consider letting them air dry, too. I don't know if silicone is meant to hold up on heat-dry in the dishwasher, but 4 months of air drying shows no cracks or anything.

Why did you pick this product vs others?: We bought these before and they fit on more cups that other ones do. I like that they come with a travel case but only one fits in the case at a time. Cleaning is very easy and because of that they don't mold.

Finally , a sippy lid that fits snugly in most toddler sized cups ! Soft for little mouths , it allows liquids to be swallowed at just the right flow so little ones don't choke. It has a slightly strong taste until it has been washed in the dishwasher a couple times which is the only negative feature I have found about it. I recommend these sippy lids for grandparents and parents alike to purchase . Great product !

They are as wonderful as advertised. When I saw the picture of the lid on a cup on its side and liquid was not coming out I knew I had to try it. I turned the cup upside down over my bed and not a drop leaked out. I have only had them a week and love that I do not have to clean all the little parts that other sippy cups have. I am keeping one lid in my purse for when we go out to eat. Well worth the money. A must have for families with little ones that need a sippy cup.

All three of these tore around the cup edge area, one after the other, so now they leak. I used them on mason jars, which do not have sharp edges. I aspire to a low-waste lifestyle, so it's pretty disappointing to throw these in the trash.

I love these. Only complaint is one already has a rip in it. I don’t know how it happened but was disappointed it could rip so easily. But otherwise these are great. Works as advertised and great we can use any cup for a spill proof life.