Supply Of Relay, Non- Ac Immune, Plug In Type Style Qn1 Dc Neutral Line 24v- Dc, 12f/4b Contacts, Front And Back Contacts Metal To Carbon With Plug Board, Retaining Clip And Connectors Conforming To Brs:930, Irs:s 34 & Irs:s 23. As Applicable.the Interlocking Code For This Unit Shall Be Abcde.