This model GE4PV Interlock Kit fits GE panels which have a 4-pole vertical-oriented main breaker and apporimately 1 1/4" from the bottom of the main breaker panel cutout edge to the top of the generator breaker panel cutout edge as shown.
 
These are very high quality kits and provide everything required for the installation including all placards, a correct size drill bit, name brand thread locking compound, all hardware  and clear installation instructions.
 
 All GenSafety Generator Interlock Kits are proudly made in the USA!