It is a mattress support system that typically uses thinner hardwood bowed slats and allows for the slat tension in certain areas to be adjusted by sliding cambers. The slats can flex and/or rotate under pressure responding to the weight and shape of the body. This can help fine-tune the alignment on the mattress and "firm up" the support under the hips or allow the shoulders to sink down more. These work best with mattresses that are thin enough for the adjustments to be effective on the surface of the mattress. The adjustable tension allows for support/comfort to be adjusted as needs change over time and provide individualized support/comfort. They are more expensive than the typical mattress foundation.

Caution: Before purchasing a mattress foundation/base it is important to always consult with the mattress manufacturer to ensure that the support system is suitable for your mattress and doesn’t void its warranty.