These mobile respirators filter contaminants to deliver breathable air without the need for an air line connection. The pump sits on your back to allow unrestricted movement, so these respirators are often used in welding, painting, and pharmaceutical applications. Made of Tychem 2000 (formerly known as Tychem QC), these hood respirators have two layers: an outer bib for overspray protection and an inner bib that tucks into your clothing for splash protection. Respirators include a rechargeable lithium ion (Li-Ion) battery that provides approximately four hours of continuous use when fully charged. Respirators have a ratchet suspension that adjusts with an easy-turn knob.