RPB Safety 03-985 PX4 High Efficiency Filter Benefit from the safety of clean breathing air without the restriction of attached airlines whether you’re welding, grinding, blasting, painting or in a laboratory. The RPB PX4 Air is a robust and versatile Powered Air Purifying Respirator (PAPR) that provides clean breathing air to the full range of RPB Safety’s industry leading respirators. Certifications include NIOSH and CE.