The NFBF-1 combines the features of a notch filter and a band pass filter into one product. The notch filter removes annoying tones from receiver audio. The band pass filter passes the desired tone while rejecting all others.

• Option A: Tunes from 1200 – 2600 Hz.
• Option B: Tunes from 700 – 3000 Hz.
• Option C: Tunes from 80 – 200 Hz.