This kit can be used to convert your enclosure into many different configurations: For example:

1- Connection between two enclosures (one inside - one outside).
2- Connection between enclosure and litter module.
3- To a pet door in wall window or patio doors.

4- An elevated crossover to another kit module or high window.

NOTE: If the enclosure can butt up extremely close to a pet door, you could simply use the special tunnel attachment panel. There would be no need for a tunnel assembly.
Order our special pane lfor pet doors only, or also with tunnel attachment kit?:
IF ordering tunnel attachment: What tunnel length? 6, 8, 12, 18, or 31 inches.
Carpeted tunnel floor (Only necessary for an elevated walkway).
If you plan to attach the tunnel to another kit module (for example a litter module or another enclosure), you'll need a second special tunnel attachment panel:
We need a few measurements to customize this kit to your requirements:
The kit is 62 inches high. We can use a tunnel access into a window or extremely high pet door as long as the TOP of the pet door opening is no higher than 60 inches. In this case, place that measurement in selection "E" instead of "A".

In a high elevated situation, the access to the tunnel from inside the cage would be either a full shelf, or half shelf - depending on height.