The 501-23749b from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 10 MHz, Supply Voltage 12 V, Phase Noise -160 dBm/Hz@100 Hz to -135 dBm/Hz@10 Hz, Phase Noise 1 kHz -172 dBm/Hz, Phase Noise 10 kHz -174 dBm/Hz. Tags: Module with Connectors, Low G-Sensitivity. More details for 501-23749b can be seen below.