Yankee Hill 4400 SRx QD Adapter 1 3/8x24 TPI 17-4 Stainless Steel 4400. YHM s sRx products were designed with ease-of-use and aesthetics as top priorities and that includes the YHM sRx Q.D. Adapter (YHM-4400). This low profile Q.D. Adapter/Mounting...