AP's or routers with WEP keys?

Hey quick question folks, Im reading both AP's and routers have WEP keys. Which one actually secures your information? You can't put two keys in right?

anything with WEP/WPA will encrypt the traffic on the network

Some give you the option to have multiple WEP keys but you can only use one at a time. It just gives you the option to change the key from time to time if you want to.

Dale