The ECS-49-20-4X from ECS Inc. International is a RF Quartz Crystal with Frequency 4.9152 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 20 pF, Equivalent Series Resistance 150. Tags: Thru Hole. More details for ECS-49-20-4X can be seen below.