Effective Coverage: It applies to villa, house, bedroom, kitchen, bathroom, living room, dining-room, wareroom, office, storeroom, etc. We recommend using one for each room, this will be better. Economic & Safe: It is normal that will increase at the beginning of the using days, hiding in the dark will be forced to appear. it will better after the use of two to three weeks, the will automatically migrate after using a month later. Easy to Use: This should be installed at 130~150 centimeter away from the floor,The installing point should be avoided from carpet, curtain etc attaching sound material, or else decrease of the sound pressure will do harm on the effect. Safe & Environment-Friendly: If placed in the warehouse / multi-item stacking place, or multi-room floor, should be put more than a few this to increase the effect. Setting it up in a children's room, a bedroom or a guest room. Keep your family have a good sleep. Wide Application: No chemicals, no radiation, non-toxic and less power consumption, 100% environmentally friendly to kids. Is widely used in home, warehouse, office, garden, hotel, etc, keeps away from where you are.