The addition of the STPAPR provides the additional levels of serviceability and comfort associated with powered air while still retaining the ability to switch instantly to the positive pressure SCBA mode when required. The STPAPR achieves this by utilising a Compact Demand Valve (CDV) fitted directly into the STPAPR.

Note: The ST53 system utilizes the NIOSH certified FM53 APR facemask as part of the ST53 system. The FM53 APR facemask can be configured to function as an SCBA, PAPR or CCBA. NIOSH does not certify or approve respirators for multi-function, combination use. The use of the FM53 APR facemask as a means for CBRN protection with an SCBA, PAPR or CCBA has not yet been approved by NIOSH.