Negative ions purify dust and allergic substances in the air to remove room odor. Safe and non-toxic. Low noise and portable. This product is an anti-mosquito weapon developed according to the mosquito's preference for a dark environment and photoaxis. it should be placed in the dark place of the room during the day, and avoid facing the lights and doors and windows, so as not to affect the effect of killing mosquitos. Just place it by the bed at night, and avoid the lighti-emitting surface of the mosquito killer facing the surface.