there are 3 backup camera solutions available on the market for your Fiat ducato vans :
1.aftermarket backup camera is cheap ,usually around USD100 for the camera and monitor ,but you need to drill holes on the roof .
2.wireless backup camera is very expensive ,usually USD200 for the complete kit with camera and monitor .the installation is easy ,no need to run cable from the back to the front .
3.original backup camera specially designed for Fiat ducato is the best solution,because no need to drill hole ,very easy installation .just check this picture :
https://brakelightcamera.com/produc...ackup-camera-fiat-ducato-peugeot-boxer-vs505/