The ECS-3951M-666-B-TR from ECS Inc. International is a General Crystal Oscillator with Frequency 66.666 MHz, Supply Voltage 5 V, Current 55 mA, Frequency Stability ±50 ppm, Operating Temperature -10 to 70 Degree C. Tags: Surface Mount. More details for ECS-3951M-666-B-TR can be seen below.