Protection like this is what it is - you just don't know until you've needed it -- luckily; I have not sustained a lightning strike; but these feel well built and I trust them... If I had a strike and my radios were saved, I'd have given it 5 stars.Arrived as scheduled. No directions. 9 months later the top screw band on the PL-259 side came off and won't hold the unit to the SO-239 of the antenna. This was carefully wrapped with coax seal. Needed to do maintenance and after unsealing the unit discovered the band outer ring had failed. Unable to re-connect to antenna.MIGHT AS WELL NOT HAVE ANYTHING INLINE..... MORE PROBLEMS THAN THEY ARE WORTH. PROBABLY WOULDN'T STOP A NINE VOLT BATYTERY SHOCK WAVE.chincy product. DONT WASTE YOUR $$$$$$. Just keep your radio, ham or cb, turned off in really bad weather or during heavy storms. There are NO instructions included.good fast service reasonable price have had no problem yet with lightning know people that it saved their equipment thanks