The 501-27183a from Wenzel Associates is a OCXO with Frequency 2560 MHz, Supply Voltage 15 V, Phase Noise -104 dBm/Hz@100 Hz to -74 dBm/Hz@10 Hz, Phase Noise 1 kHz -130 dBm/Hz, Phase Noise 10 kHz -153 dBm/Hz. Tags: Module with Connectors, OCXO. More details for 501-27183a can be seen below.