Depending upon the type and concentration of contaminant and length of service time required, MSA offers three canister models, including Type N or Super-Size, Industrial-Size and Chin-Type. The canisters are seamless to prevent leakage or channeling of gases/vapors past the chemical sorbents, kept fresh by sealing tape on the bottom air intake, which also prevents moisture from entering the canister before use. They are easy to use and store because of their compact oval shape, labeled as to type and limitations and are color-coded for fast and accurate recognition.