Minicoils or Microcoils? A previous blog article, Microcoils, covered the use of coils in mattresses that are significantly smaller than innerspring coils. In this article, I noted that some of these smaller coils are much smaller than others, and that there has not been a concensus on terminology. Until now, the whole category of small springs has been classified as microcoils. But now several manufacturers are placing two layers of these coils above the support core of a mattress....