This bushing allows the use of a 8 mm pin small hole SMG lower to mount to the semi auto receiver 9 mm pin hole large hole. Of  a converted to semi auto lower.  I have 3 kinds the steak in version will be $40  each it comes with a pin as shown plus shipping if needed.

brass and copper which fit across the whole lower will be 35 each plus shipping if applicable, they also come with a pin.

  I also have a supply of used  8 mm pins I will sell for 15 a piece plus shipping if needed. The pins are used but completely serviceable they have been cleaned checked for functiondry