... effectIt` s normal that the mouse and vermin will increase at the beginning of the using days, ... one machine is better. Effect Range:This machine will have great effect in 120--180 square meters in the ... harm to human being and pets, also will not have affect on house machine,This machine is safety ... and pests, e.g.: drug-store, haberdashery, food shop, furniture store, etc.it applies to villa, house, ...