InnoGear® 12 Volt Car Female Cigarette Lighter Adapter Socket Plug Connector Adapter
Afraid to use it again.  I plugged this in to my motorcycle battery tender leads. I then plugged in a USB cigarette adapter to charge my phone.  It popped, fizzled, and fried it to a crisp seconds later.  I am going to see if I can diagnose the problem.  Quite frankly though, I am hesitant to plug anything else in to it.  UPDATE: Leads were put on backwards. I was able to use a multimeter to determine polarity was wrong. I have since cut the leads and directly connected them to my battery. Works fine now.