The 501-25998 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 100 - 500 MHz, Supply Voltage 15 V, Phase Noise -114 dBm/Hz@100 Hz to -84 dBm/Hz@10 Hz, Phase Noise 1 kHz -142 dBm/Hz, Phase Noise 10 kHz -160 dBm/Hz. Tags: Module with Connectors, Thru-Hole. More details for 501-25998 can be seen below.