The 501-21081 from Quantic Wenzel (Wenzel Associates, Inc.) is a OCXO with Frequency 1000 MHz, Supply Voltage 15 V, Output Power 13 dBm, Output Load 50 Ohms, Phase Noise -154 to -77 dBc/Hz. Tags: Module with Connectors, Low G-Sensitivity. More details for 501-21081 can be seen below.