The OxyMask™ is a unique, open-style, oxygen mask that was originally developed in 2005. The original mask was modified, using computational fluid dynamics numerical simulations, with the goal of allowing it to produce a wider range of FiO2. This analysis was used to guide the modification of the mask shell and the location for the oxygen diffuser. The new OxyMask was attached to 10 healthy subjects and used to deliver escalating levels of oxygen (1.5, 2, 2.5, 3, 5, 10, 15, 20, 25 and 30 LPM) for 90 seconds at each level and the resulting FiO2 was recorded (at the lips) from 5 consecutive measurements at each oxygen flow rate. Mean FiO2 was 25.4% at 1.5 LPM of oxygen, 30.1% at 2 LPM, 36.5% at 2.5 LPM, 41.8% at 3 LPM, 57.6% at 5 LPM, 74.4% at 10 LPM, and 80.1% at 15 LPM. Each FiO2 achieved at these escalating oxygen levels was significantly greater than all the previous levels. The mean FiO2 was 82.8 at 20 LPM, 84.2% at 25 LPM and 84.3% at 30 LPM. All of these values on average were not significantly greater than the FiO2 achieved with 15 LPM. In a few subjects a maximum FiO2 of 90% was reached. The original OxyMask was successfully modified so that the second generation of the mask can provide a wide range of FiO2, from 25% to 90%, while keeping its unique open design.