The ECS-500-8-47Q-CES-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 50 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±10 ppm, Load Capacitance 8 pF, Equivalent Series Resistance 100. Tags: Surface Mount. More details for ECS-500-8-47Q-CES-TR can be seen below.