We’re disappointed that Sleep Number doesn’t divulge the type or density of foam it uses, calling it only a “proprietary foam.” (If customers are spending thousands of dollars on your product, we think you should tell them exactly what they’re getting.) But with the exception of the memory foam in the Cooling Memory Foam ( m7) bed-which makes memory foam its selling point-we think the foam in Sleep Number mattresses is probably some sort of non-memory-foam polyurethane foam (also known as polyfoam). And the thicker the foam portion on top, the more expensive the mattress. There’s also a layer of foam cushion that surrounds the air chamber.
