What kinds of springs are in your mattress? Metal Springs The best selling mattresses over time have been innerspring mattresses. The first mattress springs were adapted from buggy seat springs. These springs are called Bonnell coils. For a long time, they were the only kind of springs used in mattresses. Now there are several types of innerspring coils. The major kinds are Bonnell, Offset, Continuous and Pocket. Within each of these kinds are variations. Each type of innerspring has its own...