AirSkirts kits are based on the manufacturer stated length of the RV. Though your skirted area will be shorter than the entire length of your RV, we use this number because this is the number customers commonly know and is also the only length measurement consistently available in manufacturer specs.
Most trailers are measured from hitch or kingpin to bumper and coaches are measured from bumper to bumper. For many trailers, the number in the model refers to the “box length” or the length excluding the bumper and hitch (or neck in the case of 5th wheels).
To find the manufacturer’s length of your RV, you can search the year, make and model followed by the word “specs.” This database is also quite helpful.
The exception to this rule is Airstreams. The number in the model is the size kit you want to purchase. Example: a Globetrotter 25FB will take our Airstream 25′ kit, no need to search for specs.