What are the differences between the 400 series Hayden coolers? 401 Application:Normal duty driving, compact and mid-size cars Car Weight:Up to 12,000 lbs. Dimensions:5" x 12 1/2" x 3/4" 402 Application:Normal duty driving compact and mid-size cars Car Weight:Up to 16,000 lbs Dimensions:5" x 15 1/2" x 3/4" 403 Application:Medium duty driving, Mid, full size cars, pick-ups & light towing Car Weight:Up to 18,000 lbs. Dimensions:7 1/2" x 12 1/2" x 3/4" 404 Application:Heavy duty driving, Cars, trucks, class "C" motor homes Car Weight:Up to 22,000 lbs. Dimensions:7 1/2" x 15 1/2" x 3/4" 405 Application:Heavy duty driving, trucks, class "A" motor homes Car Weight:Up to 26,000 lbs. Dimensions:10" x 15 1/2" x 3/4"