End of service life indicator for respirator

Filter systems including optical analyte sensors and optical readers

Gas mask filter canister

Filter cartridge having location-registered view window for end-of-service-life-indicator (ESLI)

Permeable membrane water dissipation device

ELECTRET ARTICLE HAVING HETEROATOMS AND LOW FLUOROSATURATION RATIO

Electrets and compounds useful in electrets

Electret article having heteroatoms and low fluorosaturation ratio

Electret article having high fluorosaturation ratio

Respiratory protection device that has rapid threaded clean air source attachment

Self-powered, wearable personal air purifier

Method of making a filter cartridge using a thermoforming step

Gas mask filter canister

Dust collection system