Gas masks and canisters for gas masks have a chemical sorbent that protects the respiratory system of the wearer from gaseous compounds. The remaining service indication systems for respiratory protections systems provide a warning to the wearer that the capacity of the chemical sorbent to adsorb or absorb further compounds is nearly depleted. A remaining service life indication system has a computer memory device for storing information concerning the canister for determining an end of the service life of a gas mask, a canister and/or a cartridge and such devices from the input of various sensors.
