Does the job. Great material!

These are great for my 4 year olds bunk beds. She's had one night time accident and nothing made it through to the mattress. I'm sure if she was larger with a bigger bladder it's possible it could leak through. Takes a bit to dry but it's a good barrier for now. I will likely buy an absorbent pad to have under the fitted sheet just incase. Does take a bit to dry in the dryer, I do an extra dry cycle just to make sure the moisture is out, I imagine that's possibly why others were saying they had some mold growth.

This is a super thin waterproof cover. It’s thin enough to use with sheets then make the bed again over the top, making midnight changes easy. I was skeptical when I got it because they are so thin but after some accidents, (some not told about till the next day), have had no leak throughs; just throw it in the wash with the wet sheets, dry it and ready for the next time. I’m really happy with the product and would recommend it even while potty training.

Not as waterproof as I would have liked. Didn't let all of the liquid through but some was still more than enough.

I was really really hoping that these would be waterproof as advertised, but unfortunately they're not 100%. I got these because my dog is older now and has been having accidents around the house, and on my bed. Also for when my nephew sleeps over, and just basic protection from spills, etc. They work to an extent. A little liquid or urine- they work fine and protect your mattress. But not for "full on, full bladder being emptied" by your dog. Luckily my nephew hasn't wet the bed in a while, but I assume these wouldn't work/protect from a child full on wetting the bed either. I haven't spilled anything like a full glass of water or any type of drink, but I have accidentally spilled a small amount of water and it didn't go through to my mattress. I also have my granddaughter (and dog for that matter) who has spit-up, thrown up, etc on my bed, and the cover did protect and work. So basically, they work, to an extent. My 1 other issue is that they aren't rectangle or square shaped, they are round.. Which I find odd, but it somehow still fits on the bed because of the stretch. There's just about a 1-2 inch portion at the top, or bottom, depending upon which way you put the cover on, where the protective part ends and it goes into the stretchy material that just tucks under the bed. So there's always a small worry that those couple inches aren't protected. I just make sure to put the cover on so that part is up towards the head of my bed, where it's less likely to get wet. The King fits my King sized mattress well. The material is comfortable, unlike plastic protectors. If you make sure and pull it as tight as possible when tucking it under the bed, the protector/cover sits nice and tight on the mattress- no bunching or wrinkles. I follow/followed all the instructions and wash them in cold water. I don't hang to dry though as I don't have a place to do so. I dry them on lowest heat (which the instructions said is OK to do).