Interstate Pneumatics FA615G Brass 5/8"-18 UNF Flared x M16 x 1.5 Fitting for Gas Regulator / Gas Range. Fitting adapter connect to appliance inlet or gas supply. These fittings are manufactured from solid bar stock for a seamless, durable design. The flared end of the fitting connects to the gas connector nut. The male end connects to the gas appliance inlet, gas ball valve or gas supply stub out.