This is a replacement CPAP nasal pillow set for the DeVilbiss Hybrid Dual-Airway Interface. The Hybrid Dual-Airway Interface uses both an oral cushion and nasal pillows; this is only a replacement for the nasal pillows. This CPAP nasal pillow set fits comfortably in the nostrils to give you a sturdy seal that lasts throughout the night. It is recommended that you replace nasal pillows roughly every 3 months to keep it working at an optimal level.