Which sign indicates the length of the dangerous section of road marked with warning signs?

Explication

The plate with the number 100 between two upward arrows states the length of the road section over which the warning applies: the hazardous stretch continues for 100 metres. The advised-speed square, the distance plates and the advance STOP plate on the other cards serve different purposes — they announce a speed, the distance to a feature or to a stop, not the extent of a section.