Honeywell PAPR (powered air-purifying respirator) particulate filters and vapor cartridges install on PAPR (powered air-purifying respirator) systems to filter contaminants from ambient air. They are rated based on the type of contaminant and the percentage of contaminants removed before filtered air reaches the worker. Filters remove dry particulates such as dust. Cartridges remove vapors and gases such as paint thinner and welding vapors.