If you are diagnosed with sleep apnea and are prescribed CPAP therapy, The three main CPAP mask:

• Nasal mask: This triangular mask covers the nose only, from the bridge of the nose to the upper lip. The mask is usually held in place with a strap that goes around the head. A nasal mask works well for people who require an air pressure higher than what a nasal pillow can offer.
• Nasal pillow: A nasal pillow consists of two openings that sit just inside each of the nostrils. This CPAP mask design is lightweight and has minimal contact with your face. However, it’s not the best option if you require a high air pressure setting to benefit from CPAP.
• Full-face mask: Also called an oronasal mask, this mask covers both the nose and mouth and is usually secured in place with head straps. It is bulkier than the other mask types but works better if you mainly breathe through your mouth or require a high air pressure setting.