The 501-27387a from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 6400 MHz, Supply Voltage 15 V, Phase Noise -95 dBm/Hz@100 Hz to -65 dBm/Hz@10 Hz, Phase Noise 1 kHz -122 dBm/Hz, Phase Noise 10 kHz -148 dBm/Hz. Tags: Module with Connectors. More details for 501-27387a can be seen below.