I ordered the Flowtron BK-80D bug zapper after having used a different, smaller model, which was also made by Flowtron (model BK-7).  The BK-7 model worked okay, but quickly clogged up with bugs (pretty much each night).  After about a week of this, it shorted out so badly that it melted a hole in the plastic part which held the wires apart.  That was the end of that.  The BK-7 model used a series of round wires that go horizontally, but this tended to trap the bugs.  Even with constant cleaning, it was always giving me problems.