Open Coil, Standard Sprung, Bonnell: Same Thing, Different Names
These three terms describe the same spring system. Open coil is the general term, standard sprung is how it's often listed by UK retailers, and Bonnell refers to the specific hourglass-shaped coil design most open coil mattresses use. All three mean the same thing: a connected network of springs working as a single unit, rather than each spring moving independently.
Open Coil vs Pocket Sprung
The difference is in how the springs are built. Open coil springs are wired together directly, so the whole surface responds as one — firmer, more traditional, and cheaper to produce. Pocket springs sit individually in fabric pockets, moving independently to contour to your body and isolate motion between sleepers. Pocket sprung typically costs more and suits closer body contouring; open coil suits anyone who wants dependable, even support without paying for it.
Why Choose Open Coil
Open coil is the natural choice for bunk beds, trundles, guest rooms and children's beds — anywhere you want a mattress that's reliable and won't stretch the budget. The lighter coil unit also makes these mattresses easier to turn and rotate than a full pocket-spring core, which helps them wear evenly over time. For firmer support, our orthopaedic open coil builds pair the same spring system with a deeper profile and reflex foam layer for more structured comfort.