Size XL The ComfortGel Blue Full Face Mask by Philips Respironics blends the ComfortGel Full Face Mask with the ComfortGel Blue Nasal Mask to create a full face mask that seals with comfort. "Blue" Gel Technology Cushion The updated "Blue" gel used by the ComfortGel Blue Full Face is softer and conforms to the face better to provide an enhanced seal. Additionally, the Comfort Flap uses SST (Sure Seal Technology) to provides a unique seal around the blue gel cushion. The Blue Gel Cushion and the SST Flap can be replaced to extend the life of the mask. Fully sterilized.