Well it looks like it is a MAN KAT 1 6x6 which is supposed to be about 8.6m long in real life. Since they are using the same frame as the M35 which is 7m long in real life, that makes this baby 1/20 scale. The modern army trucks are much much bigger than their predecessors so the larger scales still looks okay (i.e. Like my 1/14 Tamiya King Hauler towing the 1/16s, and even my 1/12 HEMTT on the larger modern tanks).
It looks tiny by itself and would look even smaller among the modern tanks. It does have the latest chassis though, same as the last Russian truck, with beefer axles and transfer case as well as straighten drive train.