Zak DesignsKelso 15 oz Tumbler 2pc Set, (Campout) Leak-Proof Screw-On Lid with Straw Made of Durable Plastic and Silicone, Perfect Cup Bundle for Kids

I very much like these cups. See through, so you can tell what's in them and how far gone it may be. They are heavier, so, my kiddos was less likely to hold it with their front teeth. It's been dropped so many times and it does scuff (it is plastic, after all). The patterns are fun, they like to twist it around and tell me who all the princesses are.In terms of seal...yes and no. Sometimes I have no issue, sometimes it'll be on its side and it'll leak. Nothing different about how I twisted it or if it's loose or not. It will pressurize, so, leave juice in it overnight and it'll start coming out the top.I like how much it holds. I feel like I'm filling it up less often than other sippy cups.

My toddler loves these Zak cups! We have three of the regular plastic ones and one stainless steel, and they’re in heavy rotation at our house. The design is adorable, and the cups are genuinely leak-proof under normal use, I’d even say they’re nearly unbreakable. My little one has a habit of throwing them on the floor (on purpose!), and they still look brand new.That said, toddlers are resourceful if I’m not looking, he sometimes flips the cup upside down on his high chair tray and somehow gets a little water to leak out and make a mess. Still, compared to most toddler cups, these are by far the best we’ve tried.Highly recommend for durability, cuteness, and peace of mind!

My favorite cups for my toddler. Super easy to clean with only a few parts. The gabby dollhouse design and bright colors are something my little one loves. Light weight to throw in a bag for outings and has a good seal that rarely spills. Good price for two really good cups. My toddler finds it easy to drink out of the cup with milk water or juice. I don’t recommend for thicker drinks like smoothies functions well with thin liquids.

These are extremely leak-proof in terms of tipping and dropping, but they leak as they warm up. If you put cold liquid in and let it warm up from ambient temperature, you'll eventually see water sitting on top of the lid. After time, it'll run down the side. I don't understand why this happens since it should be able to vent and equalize pressure. I call them micro-slits, but there may be another term for it. Either way, a micro-slit exists in the straw itself and on the lid in the rubber area next to the straw. This is how they made it leak-proof while still letting air in/out. Overall, we're very happy with these. Easy to assemble, disassemble, and clean. I like the large straw diameter for cleaning too. I'd give them a 4.5 out of 5.

These were a repurchase for my son. He takes these to school and uses them around the house every day. They do not leak (but I don't recommend putting anything carbonated in them) and have held up well despite him not being easy on things. They are also a good value compared to many cups, since we tend to purchase several so we can wash daily.

My twin girls are transitioning from bottles and soft spout sippies were proving difficult. These have worked perfectly for 2 out of 2 babies, they were able to use the straw almost immediately. I appreciate being able to purchase a two-pack of anything baby related now that I have twins. The price wasn’t bad either!!

Love these cups for my two year old! He loves spidey and these were the perfect cups. They are spill proof. We had a very mild leak from milk that was left at the top of the straw. I feel like we got a good price for two cups.

I bought these cups for my 2 year old to use as a no-spill milk and juice cup. The pros are that it’s easy to clean and doesn’t leak but the most annoying downside is that you are forced to waste so much liquid. The straw maybe hits a half inch from the bottom - which annoys my toddler to the next level that there is still milk or juice left in the cup and he has no way to get to it. Also, the bottom part of the straw has a mind of its own and likes to fall out or tilt to the side with the slightly bang. If you want a cheap, leak-proof cup for water this would be okay but I don’t recommend for anything else.