Overview: The Rio II Nasal Pillow Interface is light, flexible, and quiet. Weighs only 2.3 oz making the Rio II one of the lightest CPAP mask on the market. Nasal Pillow size: Small, Medium, OR Large included. Optional separate headgear availble to make mask complete by searching " " or the following ASIN:"" Features: The nasal pillow snaps into place for easy removal or change. The mask frame has a unique vented rotating ball in socket swivel giving you a full range of motion and ideal for any sleeping position. The minimal and ergonomic design of the Rio II Nasal Interface allows an open light of sight, ability to wear glasses while on, and only requires two adjustment points on the headgear. Soft sleeves cover the cpap mask frame that touches the cheeks for added comfort.