so i was a little wary of spending more that $20 bucks on a sleep thing, but we have been through the old "4 month old learning to roll in their sleep" thing twice now, and knew well enough that we had to nip it in the bud with number 3. this thing looks so flipping goofy, but it kept her from waking herself up during that phase. she eventually started rolling around a bunch once she learned to crawl, but stayed asleep with no problems. we're still shoving her chubby buns in the 6 month size, even though she's a big 8 month old...so if anybody knows how to wean a kid off of it?