Abstract: Some embodiments of the present disclosure include nasal pillows and a valve assembly for the treatment of sleep disordered breathing. The valve assembly may include a retainer having retainer slots attached to a valve body, a flexible membrane positioned between the valve body and the retainer, the flexible membrane configured to block the retainer slots when a user exhales, and a mask coupling configured to engage with a nasal mask or a nasal pillow support. The valve body may include at least one expiratory port and a mechanism for adjusting a size of the expiratory port, wherein when the size of the expiratory port is decreased, air resistance increases, and when the size of the expiratory port is increased, air resistance decreases. In embodiments, the adjustment mechanism may be a sleeve or an adjustment screw and the nasal pillows may be replaced with a nasal mask.