LNF-xxxxxxC4.3_4.9A is ultra-low insertion loss cryogenic isolator/circulator operating in the 4.3-4.9 GHz frequency range. They have been designed from ground up to meet the strict requirements of ultra-low temperature physics research. The gold plated OFHC copper body ensures minimum loss and that this loss reaches the lowest possible temperature to minimize thermal noise. The isolator/circulator is packaged in a slim coaxial module using industry standard SMA connectors. The module measures 67.06×24.64×10.16 mm excluding the connectors.