1. Home Electricity Energy Monitoring System: The monitor is an intelligent instrument for monitoring and managing the electricity consumption in the home or building, which is composed of the receiver, transmitter and sensor. 2. Real-time monitor the electricity usage: Monitor home electronic appliances, with cost calculations built right in. Display hourly/daily/weekly/monthly electricity consumption, CO2 emission. View historical for your energy usage in historic graphical chart. Audible alert to notify of excessive usage of electricity. 3. REDUCE YOUR ELECTRICITY BILL: Measure power consumption in and cents to see exactly how much particular devices are costing you. Educate family to use energy effectively, reduce waste, cut costs down 30% which change your energy usage habits to do something for environment protection. 4. EASY INSTALLATION: Easy to install and program. No electrician required. No need to change your existing meter (sensor' clip can be installed directly onto your existing breaker box ) 5. Audible alert to notify of excessive usage of electricity Transformer Quantity:3PCS Colour:White & Black Material:Plastic Package Contents: 1 x Wireless Power Meter 3 x Transformer Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.