The ECS-135.6-12-5PX-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 13.56 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 12 pF, Equivalent Series Resistance 40. Tags: Surface Mount. More details for ECS-135.6-12-5PX-TR can be seen below.