Model SD300 Interlock Kit fits Square D Panels having a single, centered, vertical-throw main breaker spaced 3" from the top of the generator breaker as shown. The two-pole generator breaker will occupy the two top right positions in the panel as shown.
 
These kits are made in USA and are VERY high quality. The kit includes everything necessary to complete the installation including a correct size high quality drill bit, name brand thread locking compound, a complete decal set and very clear installation instructions. The interlocks are precision CNC machined and then are color anodized for extreme corrosion resistance and lifetime smooth operation.
 
Once you install an interlock kit from GenSafety you won't want to use anything else!
 
Thank you for buying USA!!