Microtek the name you can trust. I have been using microtek products since 2003 when I was in computer hardware trading. Now last 3 years I am using their inverter without any trouble. I don’t think that I have ever called a engineer. Install it and forget . It is very user friendly. A lot of survey was done When I have purchased this inverter. Its is a UPS ( Uniterrupted power supply) with LED display with CCCV technology. Some of my friends complain about After Sale Service may be I am lucky enough.