A nasal CPAP mask is any mask system that covers just the nose to deliver air for the PAP treatment. Nasal masks are generally used with a chin strap to prevent the air from going in the nasal passage and directly out of the mouth, thus eliminating the benefit of the PAP treatment. They come in many different shapes, sizes and materials. Some use a silicone type cushion to form the seal around the nose. Others use a thicker, heavier gel cushion that generally forms a better seal than other types, but are usually more bulky and heavier then the silicone counterparts. Another type are of the nasal prong or pillow style that go inside the nostrils, similar to nasal cannulas used in oxygen therapy. Masks with a silicone type cushion include the Mirage FX by Resmed, the Wisp by Respironics, and the Flexifit 407 by Fisher & Paykel. Gel cushions masks include the Softgel by Resmed and the Comfortgel by Respironics. Nasal pillow masks are perhaps the most popular type of nasal masks, since they go inside the nostrils and don’t have anything sealing around the nose since the seal is inside the nostril. Nasal pillow masks include the Swift FX by Resmed and the Optilife by Respironics. Another type of nasal mask is the cloth mask called the Sleepweaver made by Circadience. It is designed with the entire piece that forms the seal around the nose made of cloth to prevent marks on the face from over tightening the headgear straps.