The XTALUM1BE-121.755MHz-A from Dynamic Engineers is a RF Quartz Crystal with Frequency 121.755 MHz, Frequency Stability ±15 ppm, Frequency Tolerance ±20 ppm, Drive Power Level 100 uW, Load Capacitance 18 pF. Tags: Drop In. More details for XTALUM1BE-121.755MHz-A can be seen below.