Hellobee Boards

I *think* the biggest difference is sleep and plays don't have to conform to the same fire guidelines, because babies aren't mobile yet (as my 10 month old crawls around in a 9 monthsleep and play.). After 9 or 12 m they have to be snug fitting or flame retardant. Also bigger sizes have grippy feet.

So basically the same thing but looser with no grippy feet.

@Foodnerd81: Yes! Now that you say it, "sleep & plays" are definitely looser than footie PJs in the bigger sizes for exactly what you said. I think the looser fit is more comfortable and looks cuter on them.