Solo Pet Door Tunnel Extension (4" for model 1008/1210/1510/1514/1812)
For Solo Pet Doors, measure the distance from the inside wall to the outside siding, stucco, brick or stone. If the distance is 6.5" or less, no tunnel extension is required. If the distance is 6.6" to 8", a 2" tunnel extension is required. If the distance is greater than 8", a 4" tunnel extension is required.
