The ECS-500-8-37-AGN-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 50 MHz, Frequency Stability ±30 ppm, Frequency Tolerance ±25 ppm, Load Capacitance 8 pF, Equivalent Series Resistance 50. Tags: Surface Mount. More details for ECS-500-8-37-AGN-TR can be seen below.