The ECS-129.6-18-4X from ECS Inc. International is a RF Quartz Crystal with Frequency 12.96 MHz, Frequency Stability ±50 ppm, Frequency Tolerance ±30 ppm, Load Capacitance 18 pF, Equivalent Series Resistance 60. Tags: Thru Hole. More details for ECS-129.6-18-4X can be seen below.