A "foam layer" refers to a thick, fluffy substance that appears on the surface of a liquid, often with small bubbles. It is similar to the foam on top of a milkshake or the bubbles on a bubble bath. Full definition
Best of all, the special memory foam layer also gives your child more neck support which is extremely important in newborns that still are strengthening their muscles. (earlymomentsmatter.org)
The thicker middle foam layer provides unmatched support for the top layer which, when combined, makes larger dogs sleep better than ever. (dogfood.co)
From there, the high - density foam layer and subsequent high - density base provide a firm, solid foundation. (geekwrapped.com)