A working phone and a working blender united in blissful mechanical synthesis. Unfortunately, if nobody calls you, the blender doesn't blend, so waiting around for the phone to ring acquires a new urgency. Newlyweds, chatty alcoholics, receptionists on Slim Fast. Yes, for people who stick their hands in blenders. Radio-control enthusiasts who've gone the limit, Amish people interested in aviation.
Engines are very difficult to store safely.
They tend to degrade after an hour or so, and almost become useless within 10 hours. Use it or lose it. A clear, hollow plastic tube that you fill with ants and wear around your wrist. At the end of the day, free the ants and start fresh the next time you wear it. People who aren't allowed to have dogs or cats in their building, lonely people who like playing with bugs.