I have 4 kids, three of whom are now in twin beds. So, I am definitely into the waterproof mattress covers. They protect the mattress from all kinds of accidents and make it really easy and fast to change the sheets in case of a pee accident. This particular waterproof cover seems fine. However, as others have mentioned, it is super duper deep. It says that it fits up to a 20 inch deep mattress, and they are not kidding. I think if you have a big deep luxury queen mattress, then this is the one. But if you have a normal thickness twin mattress, then this will be a little baggy. Nevertheless, it seems to be good enough quality and waterproof. Material and construction: I have four kids. The oldest is 8 and the youngest is 2. Starting before I had the first, I got the waterproof cover for my mattress. I put the waterproof covers on the beds, and I put a waterproof pad under the car seat, and ever since any kind of mess a baby or child or kid makes is easy to clean up. For a parent, you need to find a good waterproof pad. So, what's a good pad? Well, basically one that is fabricy and durable and then has a waterproof layer bonded into the fabric, so that it won't tear up or separate. The bad ones are anything that is all plastic (because if it gets a little hole, it will rip all the way) and anything that is that fakey nonwoven stuff because it will separate from the plasticy layer and then shred up. This one from SensorPEDIC is fine. It's a fabric (something like a jersey knit) with a bonded waterproof layer on the back. It's zips on the mattress, which is a must because then it's on good and can't accidentally slide off. And, it covers all 6 sides: top, bottom, and 4 sides. It's the same material for top, bottom, and sides, so no worries about something running over the edge and into the mattress. The whole mattress is protected. And, no worries about getting it on and then realizing you put it on upside down and now have to take it off and start over. This is the good stuff when it comes to a waterproof zippered mattress cover. I have more than 10 of all kinds of brands, and this one is fine. Fit: So... the vast majority of mattress covers are not as deep as this one. The product description says it's for an up to 20 inch deep mattress. I got it for a normal cheaper 8 inch twin mattress. Basically, your basic bargain mattress that is always affordable. For that, this SensorPEDIC mattress cover is way baggy. It's humorously baggy. It still works, and after I put on the bedding (I use a zippered waterproof cover, then a padded cover to make it less hot, then a cotton fitted sheet) I tuck the extra under the edges and it works fine. You can use bigger bedding on a smaller mattress, but not vice versa. That said, this is Price: Right now, this is about thirty dollars. My go-to for a zippered waterproof cover is the higher end Allerease cover (Allerease Maximum Allergy). That good Allerease cover is usually a little more, but the price does overlap. Meanwhile, the slightly lower priced Allerease cover, which is only waterproof on top (Allerease Protection Waterproof) is not as good as this SensorPEDIC one. Of course, both those Allerease covers are for up to 12ish inches, but not for a super deep mattress. I think the SensorPEDIC is an OK price for a regular mattress. However, where is really shines is that if you have a deep mattress, especially if you have 14 to 20 inches deep, then this SensorPEDIC is both something that will work where you have limited options and also is something with pretty good quality and a reasonable price. Care and washing: OK, so this says you can machine wash it, then tumble dry low.. I am just going to say that a giant waterproof bag can be an odd thing to machine wash. Basically, it will have bubbles as it washes, so with a top loader, you may have to ram it down. Then when it spin cycles, it will hold big bags of water. Pretty much, I hand wash all my waterproof mattress covers in a big plastic tub in the yard. I also try to avoid washing them. I am definitely looking for something with enough fabric to hold up to use and not shred up, which this has, and also something without padding right on the waterproof cover because padding holds mess. What I do is: zippered waterproof cover on the mattress, then a nice cotton padded mattress cover, then a cotton sheet. In case of an accident, I just change the pad and the sheet, and maybe spot clean the zippered waterproof cover. Then only wash the zippered waterproof cover if it is really gross. Anyway, I hand wash in a big plastic bin, because otherwise the washing machine may not really wash it or may be imbalanced during the spin cycle. Then I hang it to dry, and basically I have to make sure it dries right side out and inside out. It's a big production, and once again, that's because it's waterproof. Also, you should never put a waterproof cover in a heated tumble drier, because if it gets super hot, it can melt. Overall, this SensorPEDIC zippered waterproof mattress cover seems totally fine. With four kids, I am a connoisseur of waterproof mattress covers, and for this one, the quality is there. As others have said, it has a super deep pocket. I think if you have a normal cheapy 8 inch thick mattress, then this may be a bit of extra fabric. However, if you have a deeper mattress that is 14 to 20 inches deep, then this SensorPEDIC mattress cover will fit your mattress well, and also is totally solid quality for a decent price. Basically, if you have a deep pocket mattress, this is the one.