The Model 51X156 is a 12-pin heavy duty socket and can be used with Time MarkÕs models 261XBXP and 261XBXPR Alternating Relays. Pressure clamp screws are #6-32 Zinc plated steel with a wire range of #12 to #22 AWG. Contacts are nickel plated brass. This socked is rated up to 600VAC and is UL Recognized and CSA Certified.. Specifications: Certifications: UL, CSA; Mount: Surface Mount; Voltage Range: 600 VAC