This pool float is only 1.5 inches thick, so it flexes down to take on some water when an adult is laying on it. That's not a drawback at all to me however as a bit of water lapping around my sides and legs feels awfully good when the sun is beating down on me and it allows me to lounge a bit longer before rolling off for a swim.It's made of foam covered by a waterproof coating that's holding up well so far to the HOT South Texas sun, and it managing to survive a couple of rowdy boys who jump on it, roll it partially over themselves as a shield during splash fights and otherwise abuse it. This is our first summer owning it, but I'm impressed that it's handled everything so far without cracking, ripping, or showing any signs of wear. We have about another full month until it'll be time to stick it in the pool house till next year, so fingers crossed. I have high hopes for it though since it seems to be doing fine.If you buy this just be aware that it's thin and very flexible. It won't keep you above the water line, but it does float well and manages to handle being jumped on, rolled up, slapped down onto the water, and other things it was never meant to have to suffer through. If you like to lay on your tummy to tan though you'll probably want to do what I do and lay with your face on the flat side and let your feet rest on the head support since it's not comfortable to lay on face down. I'll come back and update this review if my boys manage to destroy the float before the end of next month.... (they'd better not)!