or
Voice Amplifier Kit, NIOSH and NFPA 1981, 1997 Edition, Intrinsic Safety, UL Class I, II, III, Division 1, Groups A,B,C,D,E,F and G per ANSI UL 913, Canadian Std. C 22.2 no. 157-92 1987, Water-resistant Amplifier per MIL-810E (blowing rain),