YOUKUKE Electric Fly Swatter Upgraded Insect Killer, 2500V Electric Mosquito Swatter UV Mosquito Lamp Mosquito, 2 in 1 USB Electric Fly Catcher Insect Trap with Charging Base (White). Press the grey battery cover on the handle, the red indicator ‘WORKING DIRECTION’ lights up and the current builds up in the wire.
eBay