This will allow you to do things like run a blender, keurig, laptop charging, and more by giving you a pair of outlets.
Traditionally, this allows you to have an outlet just behind the driver seat on the wall, as well as just behind the slider door as well on the wall.
This harness includes enough wire to account for longer vans (except the 170EXT sprinter) and should leave you with enough wire to have to trim some!