Features: brand new and high quality If you see the for image of the BCFM radio station when you increase the gain, it looks like WFM signal interference at other frequencies, you can judge whether this is the for case. The broadcast FM band stop filter is very useful to use with SD R, because in some areas, the broadcast FM signal is very strong, resulting in SD R Overload, resulting in very poor performance in other frequency bands. The pit of this filter is relatively deep, and it will also affect the aviation frequency. This filter can suppress the signal between 88-108MHZ and has an attenuation of about 50dB or more. This filter mainly filters out FM to prevent its influence on short wave. Specifications: Material: ABS Color: black Product size: approx. 27.5x25.5mm/10.83x10.04in Package Includes: 1 x FM Band Stop Filter 1 x Accessories note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviation due to manual measurement.