While the STR Carbine Stock comes with a Sling Mount Kit - TYPE 1 (MAG333) push-button QD swivel socket pre-installed on the left side of the stock, this threaded TYPE 2 Kit can be installed on the opposite side as an additional mounting point for push-button swivels or Magpul's own QDM (MAG543). Furthermore, for running ambidextrous sling swivels on the SGA , MOE Rifle, MOE Fixed Carbine, MOE AK, Zhukov-S, Hunter 700, and Hunter X-22 Stocks, this TYPE 2 Kit must be utilized in conjunction with the optional TYPE 1 Kit. Heavy-duty black phosphatized steel construction easily installs with the STR's original hardware, or with the hardware included with the TYPE 1 Kit. Swivels not included. Made in the USA. Compatibility For use with push-button QD Sling Swivels or Magpul QDM. Threaded TYPE 2 Kit must be utilized in conjunction with the TYPE 1 Sling Mount Kit in order to run ambidextrous sling swivels on the SGA , MOE Rifle, MOE Fixed Carbine, MOE AK, Zhukov-S, Hunter 700, and Hunter X-22 Stocks. Black