The Keysight 87421A is a universal input, dc switching power supply designed to provide the bias voltages needed to operate Keysight microwave system amplifiers. These compact power supplies are ideal for integration into a system or for use on a bench top. The two-meter dc bias cable permits the amplifier to be remotely located, allowing it to be placed out of the way or where space is not critical. The Keysight 87421A is a 25 watt, 12V dc power supply designed to power the Keysight 83006A, 83017A, 83018A, 83050A, 83051A, and 87415A microwave system amplifiers. A two-meter cable is included for direct connection to the amplifier. The Keysight 87421A may also be used to provide bias voltages for the Keysight 83440C high speed lightwave converter. Using the Keysight 83440-60009 lightwave converter power supply adapter, the Keysight 87421A becomes a compact, convenient power supply for use with the lightwave converter.