The Sundstrom SR500 powered air purifying respirator is an alternative to negative-pressure filter respirators in situations where these are recommended. The fan-assisted air flow may be of benefit during extended periods of work in warm conditions. Air shield SR540 is a unique protective mask for use with SR500 and compressed air supply. The visor can be easily flipped up to a well-balanced “over-the head” position. This system means there is no hose dragging behind the user creating a trip hazard.