The 501-28131-08 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 10 MHz, Supply Voltage 12 V, Phase Noise -158 dBm/Hz@100 Hz to -138 dBm/Hz@10 Hz, Phase Noise 1 kHz -163 dBm/Hz, Phase Noise 10 kHz -165 dBm/Hz. Tags: PCB Mount. More details for 501-28131-08 can be seen below.