The 501-27521-22 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 10 MHz, Supply Voltage 12 V, Phase Noise -162 dBm/Hz@100 Hz to -137 dBm/Hz@10 Hz, Phase Noise 1 kHz -172 dBm/Hz, Phase Noise 10 kHz -174 dBm/Hz. Tags: Module with Connectors. More details for 501-27521-22 can be seen below.