1) Phone line 24 VOLTS - 50 VOLTS. 2) FLAMEPROOF CONSTRUCTION as per IS 2148-2004 ( IEC 60079-1/2001 ). 3) FOR GROUP IIA AND IIB. 4) General design , rating, performance & T-class IS:13346-2004 ( IEC 60079-0/2000 ) 5) WEATHERPROOF CONSTRUCTION IP55 as per IS 12063-1987/IEC 60529/1989. 6) Certified by CIMFR DHANBAD, INDIA. 7) Aluminum die casting body LM-6