The pest defence ultrasonic pest repeller or pest repellent ultrasonic plug in has an upgraded Quad Chip System which emits stronger low frequency ultrasonic waves at 360° which mimic like a predator; resulting stress the rodents, insects and pests away from their habitat. Continuous uses of mice repellent plug-ins and rat repellent for house works effectively to eradicate insects and pests for ultimate solution the pest defense plug in device.