The 501-27830-03 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 40 MHz, Supply Voltage 12 V, Phase Noise -123 dBm/Hz@100 Hz to -92 dBm/Hz@10 Hz, Phase Noise 1 kHz -163 dBm/Hz, Phase Noise 10 kHz -164 dBm/Hz. Tags: PCB Mount. More details for 501-27830-03 can be seen below.