BRASS COUPLING 1/2"X 3/8". 
Plain unfinished brass coupling that is 9/16" tall, 5/8" diameter. 
It has threaded 3/8" hole on one end (works with standard 1/8 IPS pipe) and threaded 1/2" hole on the other end (works with 1/4 IPS pipe). 
$2 minimum charge orders less than $20. 
$.50 packing charge for each parts box.