Safety Accessories

I have a pretty good idea what most of the bling on the boat is about, but I truly had no clue what the purpose was of the item in the photo that is mounted in the rigging of the mast. I had teased my First Mate, with my tongue placed firmly "in-cheek", that it was lightning detector that would glow if a strike was imminent.  "Make sure you watch it!" :)

It wasn't until I was talking to a slip neighbor on the pier that suggested it might be a radar deflector, though he himself was not sure as only one other boat on the pier is equipped with one.

I looked it up, and it is a reflector for radar that allows other boats (read large commercial ships) "see" a sailboat that is nearby---assuming that they have a radar, that it is in the "on" position and someone is actually monitoring the screen.