The ECS-196.6-S-18-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 19.6608 MHz, Frequency Stability ±100 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 20 pF, Equivalent Series Resistance 50. Tags: Surface Mount. More details for ECS-196.6-S-18-TR can be seen below.