The Keysight 87405B preamplifier brings reliable gain and low noise figure to measurement systems to improve overall system performance and reduce systematic errors. With its compact and portable size, this preamplifier can be powered directly from the instrument's probe-port which eliminates the need for a separate power supply and makes it an excellent choice for use in the field. The 87405B is designed for use with a variety of Keysight Measurements such as the PSA, ESA, and MXA spectrum analyzers. The 87405B is the recommended preamplifier for use with the 8594E noise figure measure ment solution. The rugged Type-N connectors stand up to the multiple connect and disconnects needed in field applications for reliable, repeatable measurements.