Cadmium sulfide flame detector. On flame failure, causes protector relay control to shut down the main oil burner. 60 in lead 2 pc. Cell plugs in a,b,e,j.P type brackets and oil line mounting brackets included. Used with protector relay oil primary controls such as R4166, R4184, R8182, R8184, R8185 and R8404. Super trade line model, ul listed, csa approved box.