The ECS-200-10-37B-CKY-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 20 MHz, Frequency Stability ±10 ppm, Frequency Tolerance ±10 ppm, Load Capacitance 10 pF, Equivalent Series Resistance 70. Tags: Surface Mount. More details for ECS-200-10-37B-CKY-TR can be seen below.