The ECS-270-18-5PX-CEM-TR from ECS Inc. International is a RF Quartz Crystal with Frequency 27 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±10 ppm, Load Capacitance 18 pF, Equivalent Series Resistance 30. Tags: Surface Mount. More details for ECS-270-18-5PX-CEM-TR can be seen below.