There are three basic kinds of spring units:
- Bonnell Coil
- Pocketed Spring.
Bonnell Springs: This Spring unit is mostly used in the firm Mattresses and though the Mattress with Bonnell Springs has the lowest coil count, the wire used is thicker. Most of the lower priced Mattresses are made with Bonnell Springs as this Spring unit costs less to produce.
LFK: This is a medium coil count spring unit and generally is more supportive than the Bonnell coil because it has higher number of springs although the wire thickness is a little less to compensate for the higher number of springs.
Pocket Springs: These are individual springs in a fabric pocket. The main advantage of the pocket springs is that they prevent “roll-together”. If two people sharing the Mattress have significantly different body weights, this spring unit will prevent the lighter person to roll towards the heavier person. This type of spring unit also causes least disturbance if one person moves. This spring unit has the highest number of coils making it most supportive.