Glossary of Mattress Spring and Bed Base Terms

This glossary gives short, clear definitions of terms commonly used in quotations and technical correspondence on Bonnell and pocket springs, mattresses and adjustable bed bases. For product-specific value ranges see the product pages.

Terms

Bonnell spring unit

A spring unit of hourglass-shaped coils joined by helical lacing wire; the supporting core of mattresses and sofas.

Pocket spring unit

A spring unit in which every coil works independently in its own separate cell.

Zoned pocket spring

A pocket spring unit divided into areas that give different support.

Micro pocket spring

A unit of small coils with a high spring density (e.g. Kings Micro).

Wire diameter

The thickness of the steel wire the spring is made of, stated in millimetres (mm).

Spring height

The height of the spring unit, stated in cm or mm.

Count

The number of springs used in a spring unit; it varies by model.

Nested arrangement

An arrangement in which rows of springs are offset and set into each other.

Edge support

A reinforced edge that reduces sagging at the mattress edge (e.g. Edge Protector).

Roll-packed

A spring unit or mattress compressed and rolled for shipping.

Flat-pack pressed

A finished spring unit pressed flat for packing.

Bed base (divan)

The base the mattress rests on; storage, trundle and corner types exist.

Box spring

A bed base type with a spring system used under the mattress.

Adjustable bed base

A bed base whose surface position is changed by a motorised mechanism.

Frame mechanism

The steel-profile load-bearing frame of an adjustable bed base.

Dual motor

The electric drive that moves an adjustable base mechanism; force is stated in newtons (N).

Topper

A comfort layer placed on top of the mattress, usually with a zipped cover.

Visco foam

Viscoelastic foam that shapes under pressure and temperature.