Resmed Mirage Activa LT Nasal Mask is the first in ResMed�s ConvertAble Series offering a choice of two high performancecushions (Mirage Activa LT and Mirage SoftGel) on the one durable frame. The Mirage Activa LT channels airflow noninvasively to a patient from a positive airway pressure device such as a continuous positive airway pressure (CPAP) or bilevel system.