When we build our conversions we always provide an external screen as we know our customers like to camp all year round and these are easy to fit and come with a storage bag.
There is a lot of glass on the vans and is not double glazed so you do lose a lot of heat and using the internal screen causes condensation between the screen and the glass the external screens eliminates this so as soon as your ready to go take the screen off and you can get straight back to your adventures no having to clean and dry window screens
 
These Silver Screens are manufactured in Italy and tailor made to fit a number vehicles including, 
Ford Transits, Fiat Ducatos, VWs, Mercedes Sprinters and other popular brands please view my other items
They offer protection against weather damage and provide internal privacy. 
When used eliminates condensation on the inside of your window screen. 
Due to their superb thermal insulation they are ideal for use in during the colder months.