The claddagh ring is a traditional Irish ring that dates back to the 17th century. The hands represent friendship, the heart love and the crown loyalty. 
   
Traditionally it is worn as such:
Single: right hand with the tip of the heart facing away from the body
Dating: right hand with the tip of the heart facing into the body
Engaged: left hand with the tip of the heart facing away from the body
Married: left hand with the tip of the heart facing into the body
 
This ring measures 3/8" in length