I narrowly missed the deadline in my state to install these prior to Rule 21 / UL1741-SA being adopted. Otherwise I would be using them myself. These are nice units. But the units are brand new, unused. Includes DC disconnect switch. Features AFCI (arc fault circuit interrupter). Is not California Rule 21 / UL1741_SA certified. (Required in some states, not in others). These are transformer type inverters so they have substantial weight. The color of the inverter is white normal for U. Units not red as shown on the box. The item “SMA Sunny Boy 4000w Grid-tie Inverter SB4000US-12 + AFCI warranty&DC Disconect” is in sale since Thursday, October 11, 2018. This item is in the category “Home & Garden\Home Improvement\Electrical & Solar\Alternative & Solar Energy\Chargers & Inverters”. The seller is “tpcboxes” and is located in Northampton, Massachusetts. This item can be shipped to United States.

• Model: SB4000US-12 AFCI
• Country/Region of Manufacture: Germany
• MPN: SB4000US-12
• Brand: SMA
• Type: Grid Tie Inverter