Annette from Duluth wrote to ask, “what does coil density mean?” You may remember when you were little having your mother, in addition to admonishing you to “keep your shoes off the bed, also insisting that you never sit on the edge of the mattress. The reason why is because the old style mattresses of yore didn’t have anything in the way of edge support, so if you spent a lot of time perched on the edge, it would eventually crush down. Back then, some of the better mattresses had “butterfly” border braces installed along the edge of the coil unit to keep it nice and firm; and they worked reasonably well. Somewhere along in the 90s, Stearns & Foster, the Cadillac of mattresses, developed a new kind of edge support. It was a “hot poured, cold cured” epoxy-like encasement which surrounded all four sides of the mattress, thus providing support for the entire perimeter. Several years later, when virtually all mattresses became “non-flip,” (padded on only one side) this system didn’t meld well with the new design, so the folks with the pocket protectors and lab coats came up with a system of inserting rigid strips of very stiff Styrofoam-like planks near the edges of the coils unit just inside the first row of springs. Again, this design worked fairly well, except the rigid inserts were too stiff, so that when you sat on the edge of the mattress, it felt like sitting on the edge of a bucket, with the edge supports cutting into the backs of your thighs. Today, nearly every quality, name-brand, innerspring mattress has a less rigid, three inch wide band of high density foam that completely wraps around the coil unit. And this is where the term “coil density” comes into play. In order to maintain a standardized mattress size, some coils have to be removed in order to accommodate the three inches of edge supporting foam. Coil density is an honest way of expressing the number springs that would have been in the mattress before some were taken out to make room for the foam encasement; not the actual number of springs. Not only does this system maintain the integrity of the edge, but it also stabilizes the mattress, so that there’s less side-to-side movement, plus a supported edge provides an additional useable sleeping area, since you can creep out to the very edge, without feeling like you’ll roll out of the bed. Please visit gotomattress.com for the absolute lowest prices on premium, name-brand bedding…delivered free almost anywhere, tax-free! Or call us, (we love phone calls) at 1-800-385-8319.