F series are economically priced connectors specially designed for use with NTSC TV ANTENNA and other similar applications. Countries using the NTSC System include: The Bahamas islands Canada, Central America, Japan, Korea, Mexico, China Taiwan, The Philippines, the USA. Etc Electrical specifications: Voltage rating: AC 150V With standing voltage: AV 500V one minute Insulation resistance: 500M ohm min at DC 500V Contact resistance: 5M ohm max at DC 1A Impedance: 75 ohm nominal VSWR: 1.2max. 0-1, 500MHz