For 2-Way and 3-Way OEM application PeterPaul's unique, unitized design offers the advantages of simplicity of installation (unit is assembled and tested requiring no disassembly) for common voltages and frequencies and carries the U.L. and C.S.A. label. Approved for hazardous locations, Class I - Group C and D (where atmosphere contains certain specific explosive gases). Class II - Group E (where atmosphere contains metallic dust), and Group G (where atmosphere contains grain dust).