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Types of Mattress Coils

Types of Mattress Coils


Drifting off to dreamland is much easier with a mattress that provides the right comfort level and support. Coils are used in the core or support layer of an innerspring mattress, and they can make a big difference in how you sleep. Below is some information on the different types of mattress coils, so you can decide which construction is right for you.

Coils in an innerspring mattress

Pocket Coils

A pocket coil system consists of barrel-shaped coils that are independently wrapped in a fabric casing to avoid constant friction. Also known as Marshall coils, pocket springs are usually pre-compressed to create a firm sleeping surface. This innerspring system allows for conforming body support and reduced motion transfer. It also fits well with an adjustable foundation or base.

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Pocket coils

Offset coils

Offset Coils

Similar in shape to a Bonnell coil, an offset coil system is constructed of hourglass-shaped coils with flat sides on the top and bottom of each spring, so they can fit together in rows. These squared ends offer a more conforming feel and deliver firm support and durability. An offset construction offers better hinging, so they're typically less noisy and adapt to the shape of different sleepers' bodies. These are often found in higher-end mattresses.


Bonnell Coils

Though not as conforming as a pocket coil mattress, a Bonnell coil configuration is comprised of individual hourglass-shaped coils for better compression-based support and a firm comfort level. The ends of the wires are knotted around the circular top and bottom of the springs for increased stability. This construction is one of the oldest and most commonly used designs found in an innerspring mattress.

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Bonnell coils

Continuous wire system

Continuous Wire System

Constructed of a single continuous wire framework that twists and turns throughout the inside of the mattress, a continuous wire spring is great for long-term durability. This design uses rows of thin wire that either runs side-to-side or head-to-toe. A continuous coil system helps reduce motion transfer so you can sleep soundly all night, even if your partner is tossing and turning. This layout is great for those who need more back support as it creates additional support in the center third section of a mattress.