Bests & Worsts Reviews from Amazon

Update 9-19-18: Recently the seller of this product contacted me regarding my previous product review written below. They asked me if they could make it right by offering me my choice of either a refund for my purchase or if they could send me a replacement order to see if they worked better than the first. I chose to allow them to send me a replacement product because I really wanted this product to work. I recieved the replacement order today and tested them out immediately and sadly, I have the same problem as with the first order - these are NOT air-tight and leak proof. I filled my Ball mason jars up with water, screwed the tops on, and shook them, and again, they leak water just like the first ones. So disappointing. When I received these, I was super excited because they look really tough and sturdy like they would get the job done. Unfortunately, Because they looked like they would work so great and be leak proof, I didn’t bother to try them within my 30 day return window. I just got around to giving them a try and they are NOT airtight or leak proof. I thought maybe I just had a defective one in my set of 4 so I tried another one, and then all the rest of them and they ALL leaked water everywhere when shaking or turning upside down while screwed onto a Ball Wide Mouth Mason Jar, Quart size. Very disappointed and it’s too late for me to return these. Not happy at all. I don’t even understand how or why they leak because the design seems like it would work flawlessly and I don’t notice any obvious defects.