When you put a stamp on a letter, you think of the 49 cent sticker you put in the upper right hand corner of the envelope.
But walk into a post office or Mail & More in Dublin and your mail could get a different stamp.
For the last 30 years, the Dublin Service League has offered to ink stamp a shamrock or leprechaun on your mail.
Folks can use their letters and packages to spread the word of Dublin's Saint Patrick's Day festival.
As of noon Tuesday, the Dublin stamp went as far away as Hawaii.
Audrey Hogan with Mail & More says people are unsure at first.
“Customers are a little bit shocked. They think it's a fee. So, we gladly offer it free. It just kind of spreads the St Patrick's festival; our news about our festival through the country,” said Hogan.