The ECS-300-S-20A-F-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 30 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 20 pF, Equivalent Series Resistance 40. Tags: Surface Mount. More details for ECS-300-S-20A-F-TR can be seen below.