Swivel Chair Gas Spring with Integrated Depth Spring Action. Additional spring force provides a buffer for preventing undesirable spine compression when sitting down. In addition to comfortable spring properties over the entire adjustment range, the STAB-O-MAT ID gas spring with integrated depth spring action offers improved shock absorption particularly in the lowest seat position. The STAB-O-MAT ID features a special end stop buffer for enhanced comfort. The highly progressive force increase of the locked gas spring in the compressed position has been optimized by providing a groove in the guide tube.