YAESU YF-122CN CW Extra Narrow 250Hz for FT-897D, FT-857D, FT-817ND YAESU YF-122CN NARROW 250Hz CW Filter Selectivity(-6/-60dB): 250 Hz/2.0kHz Fits models: for FT-897, FT-857, FT-817 and FT-2000(sub receiver) Center Frequency:455kHz