Clinical trial with crossed groups, open, masked for the evaluation of the main outcome. Inclusion of all premature infants with a birth weight less than 1500 g requiring Non-invasive Ventilation (NIV). Premature will be randomised to start alternatively with MT or 3DM. Each patient included will be their own control at the same time, receiving each of the different mask models every 4 hours alternately. The study period will be a maximum of 7 days. To compare the time in which preterm maintain SatO2 below 85% with the 3DM versus the traditional mask (TM) in preterm \< 1500 g. Other secondary objectives regarding ventilation enhancement will be assessed, such as the number of bradycardias, cardiorespiratory arrest and need for resuscitation in the context of apnea. Also, skin lesions of the nose resulting from the pressure applied by any of the masks (TM or 3DM) and the need for analgesia and/or sedation for pain control or discomfort will be assessed. Parental perception and satisfaction will be assessed.