A very good belt, which completely fulfilled its purpose, safely transport the dog in the back seat of the car, but: NOTE: 2 carabiners are advance to screw on the car seat, noting that the 1 on the waist belt and the 2nd on the shoulder strap. For me this was primarily as not clear from the instructions. If you follow exactly the image and mounted both carabiners only on a belt, so can not turn while driving the dog. When trying to lie down, he threatens to get entangled in the straps and to strangle himself. Our holiday was so one way for the dog very stressful, he could not rest (which fell on without an explanation was recognizable). By chance, I came on the way back also to sit in the back seat so that I could detect the error and correct. Properly mounted (a carabiner on the waist belt, the second on the shoulder strap) and all is well.
Supplement (currently after returning from vacation in August 2014)
Size L is probably a bit too big for our Eurasians (Chest 80cm), but it works (better than too small). It is true, as well as other notice that the dishes are somewhat bulky and the dog is not thrilled to wear a quasi "saddle" on the back. He is yes but only briefly shown around so that during a rest time. The bottom line is the safety while driving and mounted correctly (see above), a relaxed driving guaranteed.