When the German military took delivery of the first vehicles, they immediately put them to the test on- and off-road in snow and ice to test their capability at handling European winters. Several four-wheel-drive vehicles were used as reference points. The two-wheel-drive "Kübelwagen" surprised even those who had been a part of its development, as it handily out-performed the other vehicles in nearly every test. Most notably, thanks to its smooth, flat underbody, the "Kübel" would propel itself much like a motorised sled, when its wheels were sinking into sand, snow, or mud, allowing it to follow tracked vehicles with remarkable tenacity.