It looks like a seal out of a gardenhose spray nozzle.
We need to know what type of metal it is and what size it is at the very least to attempt to id a relic. Location of the find is often helpful (house, farm, field, woods...) as well as what other relics that were found nearby.
In short, the more info you can give, the more likely you are to get an answer.
Please read this: http://www.treasurenet.com/forums/what/136849-please-read-before-posting-items-what.html
DCMatt