The gas spring helps adjust the seat height on this equipment. It is attached to the seat assembly and frame. Quarterly inspection of the gas spring on your Precor AMT885 series equipment is one way to keep your fitness machine in safe working order. We offer quantity discounts on this high-wear item. There is a 90-day warranty from purchase date on NGS sales invoice. This 140mm stroke, 150 lbs, is compatible with OEM #301216-102 or 301216-103. See also our part #PR1215, Gas Spring Ball.