Here's the explanation:

'Rise' is a term invented by Patio Pacific many years ago and generally adopted by the industry. It refers to the height of the flap above the base of the pet door.

'Rise' is very important to the comfort of your pet. A higher rise gets the flap up higher for a taller dog which avoids him having to stoop to get through.

On the other hand, a lower 'rise' is less to step over.

In the past, a consumer that wanted a different rise for any reason had to buy another door. If you misjudged and got a door with too tall a rise you were in trouble. Likewise, if you replaced a short pet with a tall pet or vice-versa, you had a problem.

The adjustable rise concept greatly increases your flexibility with the pet door. By simply removing the bottom flap assembly and cross pieces with a Phillips head screwdriver, you can rearrange the order of the cross pieces to get the rise higher or lower.

This patented feature is only available on the Thermo Panel IIIe, the Quick Panel III and the Pet 1 Panel which offers the user adjustable rise under license from Patio Pacific Inc.

The flap assembly and cross pieces may be reinstalled in various combinations to change the 'rise' of the panel. The #8 is shown with 3 'rise' options.

These parts were removed from the panel at top with the Phillips head screwdriver shown.