In order to determine what size Elite cover you need for your vehicle, please follow the suggestions below;

For a truck, Class B Van and Class A RV, you will need to know the length of your vehicle. For Hummers, go directly to the chart below and look at the description to determine your size. You can either measure your vehicle from bumper to bumper and refer to the chart below or you can try your favorite search engine and look up your year, make and model of your car's dimensions. Example; In the search bar type 2006 Ford F150/dimensions.  Then it should have a sub category such as "exterior" which will have the dimensions of your vehicle. Once you have the length of your vehicle refer to the sizing charts below to find out what size you need. For trucks you will also need to know your truck's bed length.

Trucks
Size TS0 fits compacts up to 15' before 1980 / 14.5' L x 65" W x 58" H
Size TS1 fits compacts, standard cab, short bed up to 16' / 15.5' L x 65" W x 58" H
Size TS2 fits compacts, standard cab, long bed up to 17'6" / 16.5' L x 65" W x 58" H
Size TS3 fits compacts, extended cab, long bed up to 17'6" / 17.5' L x 65" W x 58" H
Size TS4 fits compacts, crew cab, 6' short bed up to 17'6" / 17.5' L x 65" W x 58" H
Size TS5 fits compacts, crew cab, 5.5' short bed up to 17'6" / 17.5' L x 65" W x 58" H
Size TS6 fits mid size, crew cab, long bed up to 18'6" / 18.5' L x 65" W x 58" H
Size TS7 fits mid size, crew cab, 6' short bed up to 18'6" / 18.5' L x 65" W x 58" H

Size T1 fits full size, standard cab, short bed up to 17'6" / 17.5' L x 75" W x 64" H
Size T2 fits full size, standard cab, long bed up to 19'6" / 19.5' L x 75" W x 64" H
Size T3 fits full size, extended cab, short bed up to 19'6" / 19.5' L x 75" W x 64" H
Size T4 fits full size, extended cab, long bed up to 21' (includes dually) / 21' L x 75" W x 64" H
Size T5 fits full size, crew cab, short bed up to 21' (includes dually) / 21' L x 75" W x 64" H
Size T6 fits full size, crew cab, long bed up to 22' (includes dually) / 22' L x 75" W x 64" H
Size T7 fits full size, crew cab, 5.5' short bed up to 19'6" / 19.5' L x 75" W x 64" H

Hummer
MH1  fits SUV
MH1T fits Open Top Truck
MH20 fits model without spare tire
MH2 fits SUV
MH2S fits SUT
MH3 fits SUV with spare tire
MH30 fits model without spare tire
MH3S fits SUT truck type

Class B Covers
Size V3  fits up to 18' w/no bubble top 216"L x 82"W x 73"H
Size V4 fits up to 19' w/24" bubble top 240"L x 84"W x 84"H
Size V6 fits up to 21' w/24" bubble top 260"L x 84"W x 84'H
Size V7 fits up to 21' w/36" bubble top 260"L x 84"W x 96"H

Class A RV Covers
Size RVA1 fits from 18' - 20'
Size RVA2 fits from 20' - 24'
Size RVA3 fits from 24' - 28'
Size RVA4 fits from 28' - 30'
Size RVA5 fits from 30' - 33'
Size RVA6 fits from 33' - 37'
Size RVA7 fits from 37' - 40'
Size RVA8 fits from 40' - 42'