The F-14 measures currents on 50 Hz, 60 Hz and 400 Hz powerlines. All the F-14 current probes except the F-14-C have a usable frequency range of 10 Hz to 500 kHz. A power absorbing terminator can be added to provide a high quality blend of high sensitivity, power handling capability and broad bandwidth. The basic F-14 curent probe has a flat transfer impedance of 0.12W (± 2 dB) from 100 Hz to 500 kHz. The F-14-1 with a power absorbing terminator has a transfer impedance of 0.025W (± 2 dB) from 30 Hz to 500 kHz. The F-14 and the F-14-1 can operate up to 400 amperes of primary powerline currents DC to 400 Hz without saturating the probe. Custom variations of the probe are available. The primary difference between these custom versions of the probes is the specific location of the flat region of the bandwidth.