Ael crystals hc 49u quartz crystal resonators through hole ael x3m579545l031 a 3579545mhz crystal resonator with a tolerance of 30ppm in a hc 49u style holder that is suitable for a wide range of frequency control applications and serves as direct replacement for existing designs ael x3m579545l031 3579545mhz hc49u quartz crystal resonator