The STO-0820300-C-E1 from ERAVANT is a Vector Network Analyzer Extender with Extended Frequency 90 to 140 GHz, Input Frequency 11.25 to 17.50 GHz, LO Frequency 11.25 to 17.50 GHz, Output Power -5 dBm (Test Port), Input Power -3 to 3 dBm (RF), 0 to 6 dBm (LO), 25 dBm (Damage). More details for STO-0820300-C-E1 can be seen below.