Offer respiratory protection against a specific gas or group of gases, as indicated by canister identification. The gas mask assembly has the following Maximum Use Condition: Entry - 100x the Permissible Exposure Level; do not exceed the Immediately Dangerous to Life or Health (IDLH) concentration. Escape - contaminant concentrations up to the maximum use concentration of the gas mask (generally, 20,000 ppm (2% by volume); see canister selection chart for details), providing there is adequate oxygen (19.5% by volume) to support life.  At these upper use conditions, the service time may be as short as 12 minutes. The Super-Size gas mask has an extra-large canister, which will last approximately twice as long as the equivalent Industrial-Size canister because of a larger volume of chemical fill.