STE-KF412-S1 is a high output power E-Band X4 frequency extender that uses an input frequency range of 15 to 22.5 GHz at +5 dBm along with harmonic generation and filtering to produce a 60 to 90 GHz RF signal. The extender features an adjustable attenuator for output power control. The extender is designed and manufactured as a bench top unit to extend the low frequency synthesizer or sweeper, such as Eravant models STL-SG-022403-S1 or SOT-02220313200-SF-B6, without losing all of the functionalities and features. The extender also features adjustable legs, which can also be removed, to allow for an easy test set up.