ZH dogs work on the inside whereas ZFH dogs are field dogs working on changing terrain and work spots with the additional requirement of illegal immigration. ZFH training requires successful pre-training of Schutzhund or equivalent or training from scratch. As with ZH dogs suitcase and container work along with body search is performed but with a less weight average. The trainee is highly trained on tracking in various terrains and environments as well as whether conditions. These dogs are more like patrol dogs working on a countries border lines. Training is carried out in the same manner as ZH training. K-9 dogs can attend the program as a specialty branch being ZFH + .