White-rodgers mercury flame sensor, 48″ element, 30a46-5 plug-in feature requires no additional electrical connections or mounting devices, sensor combines a rugged snap-action spdt switch and powerful mercury actuated thermal element, may be used with natural, manufactured or mixed gases and with lp gases where means are provided for obtaining automatic pilot gas shut-off, no button to depress- sensors are recycling type which require relighting or possible restoration of proper gas pressure to return to operation.