It is a simple serrated split disk that attaches like a shaft zinc. It has worked twice in the last 6 years, and has not failed to work. It's kind of a non-event -- you might hear a bump under the boat and say "did we hit something?" then turn around and see a buoy floating in your wake.

I try to be vigilant and avoid the floats. Sometimes they're underwater, hidden by reflections/waves, or at night and you just can't see them.

I consider it a safety precaution. You do need to clean it regularly to keep it growth-free.