IMPORTANT NOTE: Only works at night! Use in completely darkness for best results. Other light sources will interfere with the normal operation of the device. You can leave the device on overnight in a room to make sure that room is mosquito/fly free the next day. Completely non-toxic and non-chemical. This is an environmental and family friendly solution to pest problems. Includes manual in English. For outdoors, use only in a covered, protected area; for example, a garage, screened-in porch or four-seasons room. Item supports 110-220V (US or EU power plug).