The 501-26845 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 250 MHz, Supply Voltage 15 V, Phase Noise -112 dBm/Hz@100 Hz to -82 dBm/Hz@10 Hz, Phase Noise 1 kHz -142 dBm/Hz, Phase Noise 10 kHz -159 dBm/Hz. Tags: Module with Connectors, Low G-Sensitivity. More details for 501-26845 can be seen below.