CSpring MK3 CPAP Humidifier Water Chamber Refilling SystemThe CSpring MK3 Automatic CPAP Water Chamber Refilling System keeps your CPAP humidifier topped up so you do not have to refill it every night. Water level sensors monitor the chamber and replenish it from an external reservoir, keeping humidity consistent through your therapy. It works with the ResMed AirSense 11, AirCurve 11, AirSense 10, and AirCurve 10. Setup takes a few minutes and no tools: you replace your humidifier's top lid with the CSpring