Load Center Manual Transfer Interlock Kit

This is for the Leviton load center "Interlock Kit" for a standby generator. I just had a new garage built, they installed a Leviton 200 amp load center (nice shiny white cabinet !). I asked the electricians to include capability for a standby generator. They pointed me to the Leviton Interlock kit that could be purchased and installed and thus negate the need for a separate transfer switch. I looked into it, wanted to make sure it was UL approved - and, thus, be Code compliant. I purchased it from Supply House - best price I could find. Delivered in only 2 days - Great !! I installed the interlock instead of having the electricians do it. The town inspector approved all the electrical work including the interlock. Pretty straight forward to install and seems to be robust enough to perform the intended function. (The Leviton instructions indicated that only two holes and screws were to be installed. However, the actual hardware required three holes and included three screws. No big deal, but someone at Leviton should update their documentation to match the actual hardware.)