REMstar® Plus with C-Flex™ is the perfect combination of the advances in technology. On the surface, it's easy to trace this device's lineage — it's pure REMstar from its sleek design down to its integrated heated humidification unit. But therapy with C-Flex is a totally unique experience. The difference is the C-Flex waveform which offers a more comfortable way to deliver sleep therapy by taking the work out of exhalation.