Like new Resmed Aircurve 10 ST with 531 hours. Save $2000 off the price of a new one (I purchased this new in November 2025). This is a bilevel device with a backup rate and Ti control. Four operational modes: S-spontaneous S/T-spontaneous/timed T-timed CPAP-conventional cpap. Clinical indications for ST therapy: COPD, neuromuscular/restrictive disorders, and obesity hypoventilation syndrome. Includes machine w/humidair water chamber, power cord, new slimline tubing, case, and manual.