Please noted,PV INVERTER type have to connect Inverter for A source,Inverter and PV system as main power.The stable grid power for B source. The purpose of use is photovoltaic as the main power source,and the backup power source is the utility powerDual power switch. PC level,no Interrupt.Only for for PV system and Inverte to city power,not for city power and Generator to city power and Generator.Different batches,the batch number characters on the product may be different,it does not affecttype: 63AColour: white + blackMaterial: PCSize: 107 x 96 x 76mmPackage Contents: 1 x Automatic Transfer SwitchOnly the above package content,other products are not included.Note: Light 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.