Sold individually. One shouldered zen pin for the Goose Balisong designed to be used in the safe handle to enlarge the handle gap and hide the spine in the handle in the closed position.  This does increase the handle gap when in the open position as well. 
 
Two pins can be purchased in order to keep the handle gap centered with the blade, as installing only one pin will make the open handle gap look a bit offset with only the safe handle moving out.
 
Made to order and usually ship in 5-7 days.
These pins are manually machined and some minor variance is possible.