I thought the caps would be tighter. I used them to transport water in a 5 gallon jug. I had to keep the jug sitting upright due to potential for spilling.These definitely are super snug and no water will leak. The only thing I have to say is that it’s so hard to take this lid off!It's a fantastic idea but the design and stability could use some work.These work pretty well, no leaks or anything. They are really hard to get off tho and either have to be cut off or ripped off with my teeth - making me look like a crazy lady in Walmart hahaSeals great,We refill our 5 gallon jugs at a local well, and needed something reusable to keep the water inside. These apply VERY well and are snug and secure.... until you need to get them back off. They are a serious pain, you stretch the plastic, and then they're not snug anymore. We went with a different style since these are not usable anymore.Its pretty sturdy. Ive cut it up to a small size so i can reused them because i just lost the cap to my jug and it fits great. There arent any leaks when it has water in it. Great for replacement caps to these kinds of jugsThese definitely protect your water from getting contamination and they fit tightlyBought a couple of 5 Gallon Italian Glass Water Jugs - unfortunately they didn't come with stoppers. After looking over a number of 5 Gallon Water Jug stoppers I decided to try these ones out. Tried them once they arrived on one of the Glass water Jugs and after a solid push it fit snuggly over the jug opening. I did get it off after a few seconds of prying and twisting but it was clear to me these stoppers are quite suitable for the Italian 5 gallon Glass Water Jugs I got. Now to fill the jugs and stopper them up.Si pueden funcionar en garrafones normales no en los de rosca que yo tengo ?Solo puedo comentar que es un Excelente producto, muy útil.No le queda a los Bonafont no cielProduct just as described.