The Ultrasonic Mosquito Eliminator is said to be able to take care of annoying mosquitos using ultrasonic waves.
You charge the little gadget by winding it up. 1 minute of winding will give you 2 hours of mosquito elimination. So stop wining and start winding you ways to an evening free of bloodsuckers.
No idea if this works. If not, you’ll at least have a built in flashlight as a bonus. No information available on pricing or where it can be purchased.