Good knight Power Activ+ System is the most technologically superior mosquito repellent machine. The pack consists of 3 units of mosquito repellent refill. The machine comes with dual-mode technology. The liquid mosquito repellent refill contains 50% more Activ Molecules which makes it 50% more powerful. It ensures low electricity consumption a consistent release of the Power Activ+. Good knight Power Activ+ System is absolutely safe to use around children and family.