Bonnell spring coreNB, Mini Bonnell spring coreSB
Bonnell spring units consist of individual improved springs with wire ends tied at both sides and joint with a steel wire, or a spiral.
Pocket spring coreT, Micro pocket spring coreM, S1000S, S2000SD
Pocket springs consist of individual springs in fabric pockets. The individual springs are bonded to form rows of springs with a fabric.