Firefighters are required to use a self-contained breathing apparatus (SCBA) for respiratory protection when engaged in a variety of firefighting duties. While the SCBA provides crucial respiratory support and protection, it is also cumbersome and heavy, thus adding to the physical work performed by the firefighter. The purpose of the present study was to evaluate and compare the low profile SCBA prototype to a standard SCBA, as assessed by the objective and subjective measures of mobility and comfort, time of donning/doffing, as well as by acquiring user feedback on SCBA design features during field activities. The results of the present study indicated that the prototype SCBA was rated as a significant improvement over the standard SCBA in the areas of range of motion (ROM), mobility, comfort, induction of fatigue, interaction with protective clothing, and operability when worn over a standard firefighter ensemble, while performing a series of International Association of Fire Fighters Fire Ground Survival Program training exercises.