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What is a Bonnell Coil?

A Bonnell coil system is a configuration inside an innerspring mattress that uses hourglass-shaped springs. The ends of the wires are also knotted around the circular top and bottom of the springs. This construction is one of the oldest and most commonly used designs found in an innerspring mattress. Its unique knotted arrangement helps create a firm and stable sleeping surface.

Benefits of a Bonnell Coil System

  • A Bonnell coil system gives sleepers firm support thanks to its hourglass-shaped design.
  • This configuration increases stability with its knotted-ended spring.
Learn more about other innerspring options in the mattress buying guide