RPB Safety LLC 03-955 PX4 Battery Long life, lightweight, Lithium, rechargeable battery. Operates up to 13 hours on a single charge. Has a quick test button to view the current battery charge. 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.