The ECS-153.6-18-18-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 15.36 MHz, Frequency Stability ±100 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 18 pF, Equivalent Series Resistance 50. Tags: Surface Mount. More details for ECS-153.6-18-18-TR can be seen below.