This a stop band filter with approx 50db of attenuation between 50Mhz and 100Mhz, 

it was used to reduce receiver interference from high power VHF transmitters (eg pagers & FM broadcast).

I have opened a unit to show the internal construction

This filter could be used as designed or as a starting point for someone wanting to build their own multistage filter

You will receive a used unopened filter in similar condition to the photo.

Ship to Ireland and the EU (Spain mainland only)