HQRP 500W Grid Tie MPPT Power Inverter. The grid-tie inverter transfers solar energy directly from the solar panel into the home grid, no extra equipment is needed. It controls the phase, the frequency and voltage of the power generated by the solar panel. It can be connected to any outlet (conventional network) in the home. The grid-tie inverter produces a pure sine-wave and matches that of the grid. HQRP UV Chain / UV Radiation Tester: To know the Solar UV Index, it is enough to compare the colorchange with the 4 standard colors around. Very light purple: low intensity, UV index 1-2. Sun-protection not necessary. Light purple: medium intensity, UV index 3-5. Sun-protection is recommended. Purple: strong intensity, UV index 6-7. Sun-protection is necessary. Dark purple: very strong intensity, UV index 8-11. This tester shows you the level of UV radiation and helps you protect your eyes and skin from negative sunlight effect.