1. It's high Amp item, and the device needs certified and professional electrician for wiring. 2.The frequency of the wireless router is 2.4GHz. 3. The meter requires the measured device must have neutral wire. otherwise it can't measure the device's voltage, current, and power. When you install the CT , please note the CT's direction, make all 3 CT with the same direction. With External Antenna for Strong and Stable Signal Type: 120A Material: Plastic colour: White+Black Package Contents: 1 x KWH Meter 1 x Antenna Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.