The T4 is a very popular base for building a small to medium-sized camper and day-vans, both as self-build projects and for professional conversions. Volkswagen themselves also sold campervan versions of the T4. Outside of the US these were made by and named after their contractor, Westfalia-Werke. These Westfalia built campervans were named 'California', except in Canada where they were called simply 'Westfalia'
