In two different models that is the bottoms of the standard models.

This is the model that Sacro Ease began with 70 years ago. The rubber supports and steel fame absorb road vibration - not allowing it to transfer to your spine. McCarty's Sacro Ease has become a fixture in the world as one of the most effective supports available today.

Simply one of the most effective ways to "rebuild" an unsupportive seat or chair. These basic bottom only models are rated among the best ~ used by people in all modes of sitting.

Dimensions:
Small - 16" L x 15" W x 1" H; Weight: 3 lbs.
Medium - 16" L x 19" W x 1" H; Weight: 3 lbs.