The loose fitting face shield and SR 500 belt mounted Powered Air-Purifying Respirator (PAPR) protects against particulates,gases and vapors, or a combination. The SR 500 PAPR system functions as an alternative to Air Purifying Respirators(APR) in all situations for which these are recommended. The above-atmospheric pressure thengenerated prevents pollutants from the surroundings from penetrating into the breathing zone. This applies particularly towork that is hard, warm or of long duration.