Coffee flavor killers are oxygen, moisture, Co2, and light. Put your coffee beans in this canister and keep your beans fresher for longer. Has a built-in Co2 AirFresh valve, which allows Co2 to escape one-way and with an airtight seal keeping oxygen out. As long as you keep the canister away from heat sources, your beans will stay fresh and the flavor will be maintained for much longer. Keep track of the beans freshness with the built-in calendar wheel! Holds up 17oz of your favorite coffee beans.