Philips Respironics has been doing a lot of listening. They have loaded many of their machines with intelligence because they gathered yours by paying attention to your wants and needs! The Philips Respironics BiPAP Pro Bi-Flex Machine with Heated Humidifier is a perfect example! It is a fixed BiPAP machine that provides two levels of air pressure: a higher pressure when you inhale and a lower pressure when you exhale.