The 501-26838a from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 500 MHz, Supply Voltage 15 V, Phase Noise -121 dBm/Hz@100 Hz to -91 dBm/Hz@10 Hz, Phase Noise 1 kHz -146 dBm/Hz, Phase Noise 10 kHz -170 dBm/Hz. Tags: Module with Connectors. More details for 501-26838a can be seen below.