Hardin Marine has done it again! This new all 316L stainless steel fabricated thermostat housing replaces the old, and no longer made cast iron units used in Mercury 850, 1075, 1200 SCi and other applications. Replaces Mercury #840047A02 and #8M0192206 housing and #849875T01 cover. Water inlet is -16 ORB. Circulation Hose bung is 1-7/8". All 4 header and tailpipe fittings are 3/4" NPT. You must reuse their original OEM ball and stud assembly in the tailpipe outlet. Includes 160 degree thermostat, O-rings and hardware needed to install. Fittings are sold separately see related parts.