Raltron A-19.6608-18

the amount of capacitance measured or computed across the crystal terminals on the PCB. Frequency Tolerance. Frequency tolerance refers to the allowable deviation from nominal, in parts per million (PPM), at a specific temperature, usually +25°C.

the maximum allowable deviation from the nominal crystal frequency at a specified temperature, usually 25℃. The recommended frequency tolerance of the crystal over the manufacturing process is ±50 ppm.