Use with any Breathe Easy™headpiece. Dependable, high-performance turbo units ensure a continuous flow of cool, filtered air for up to 8 hours. Belt-worn turbo units come with rechargeable NiCad battery pack, belt airflow indicator, and Breathe Easy™Systems instruction manual. Combo Cartridge PAPR is intrinsically safe for combustible atmospheres and explosive areas. SmartCharger® recharges batteries in 6 to 8 hours. Can be used with both single and combo cartridge units. Battery packs will not overcharge and can be left on charge for up to 30 days. NIOSH approved. *Uses Battery Charger 3M520-03-73