S4 or S4/S8 BFOU(c) 250V Armour& Collective Shielding fire resistant NEK606 ... retardant, low smoke, halogen free and mud resistant, used for instrumentation, communication, control and alarm systems.Standards :IEC 60092-376IEC ... thermosetting compound, SHF2 (for TYPE S4). Halogen free MUD resistant thermosetting compound, SHF MUD (for TYPE S4/S8), coloured grey (blue for intrinsically safe).Electrical ...