The ECS-100-18-4X-CKM from ECS Inc. International is a RF Quartz Crystal with Frequency 10 MHz, Frequency Stability ±10 ppm, Frequency Tolerance ±10 ppm, Load Capacitance 18 pF, Equivalent Series Resistance 60. Tags: Thru Hole. More details for ECS-100-18-4X-CKM can be seen below.