The ECS-500-10-33-RTN-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 50 MHz, Frequency Stability ±20 ppm, Frequency Tolerance ±15 ppm, Load Capacitance 10 pF, Equivalent Series Resistance 40. Tags: Surface Mount. More details for ECS-500-10-33-RTN-TR can be seen below.