The Ultimate Crib Sheet is a combination mattress pad/cushion, sheet protector, and waterproof pad, and I rave about it to anyone I know who's expecting a baby or who's just had one. This product was an absolute lifesaver when my son was born. (I listed it in Baby Furniture because there really wasn't a category for Baby Bedding.)
The Sheet lays on top of the crib mattress and attaches by straps that snap around the crib bars - one at each corner, and two in the center, on either side of the sheet, so there are six snaps altogether. From the side, the crib bedding is still visible, so you don't lose the view of the cute sheets and comforters you bought for the nursery. So it's nice and comfy for your baby. But when it really shines is those middle-of-the-night wake-up calls for a wet diaper.
Baby soaked through his or her diaper at 3 AM? No need to change all of the crib bedding, just snap off the Ultimate Crib Sheet. The bedding underneath is nice and dry, and you just snap on another Ultimate Crib Sheet, change the baby, and you're good to go. I loved this product. My son was a diaper-soaking champ, and when it was the second or third change of the night, I was very, very grateful that I didn't have to take all the bedding off and put it all back on.
The product description says it holds up to four cups of liquid. I never measures, but like I said, my son was a diaper-soaking champ, and I never had any problems with the Ultimate Crib Sheet absorbing it all. They were used heavily at my house, and they held up well to repeated washings and dryings.
This is now my standard gift for baby showers, and I don't think new parents can afford to be without it!