Model SD275 fits Square D "QO" panels which have a single, centered, vertical-throw main breaker spaced 2 3/4" above the top of the branch breaker columns as shown.
 
The two pole generator breaker will mount on the top of the RIGHT branch breaker column.
 
This kit is not yet a full production run kit, so all components are not our signature blue anodized color. It is precision CNC machined from solid aluminum billet however, and looks very professional and fits very well. The kit includes everything necessary to complete the installation including all hardware, the correct size drill bit, name brand thread lock compound, a full warning placard set, and clear installation instructions.
 
All of our interlock kits are proudly made in the USA!