The Sliding Glass Door Adapter allows the Smart Pet Door to mount onto a pet door that is built into a sliding glass door insert. This adapter is usually required in these installations because window trim near the in-glass pet door can interfere with operation. The adapter creates space for the Smart Pet Door to fit over the sliding glass insert frame and securely mount onto the existing pet door frame.
The 'dado' is the groove in your door or window frame that allows the glass to slide in. In most cases this depth is 1" (25 mm) if yours is not please contact Pawport Support.