Original WW 2 US Army Overseas bar.  
Yellow machine embroidered thread on OD wool.  
These are (EM) enlisted man's style but can be worn by all ranks.  
Worn on left sleeve for service overseas during WW 2.  
Each bar represents 6 months service overseas.
Size is 1 3/4 x 2 inches.
 
This listing is for one, 4 bar patch, photos shows front and back.