Fatigue rated means that the load cells are designed in such a way that they can withstand a practically unlimited number of load cycles without the load bearing components weakening. Think of most of the objects you use on a regular basis. The more you use them, the more they wear out until eventually they break, and you need to replace them. Fatigue rated systems offer an excellent benefit that is practically infinite fatigue life.
What this means is that as long as a certain stress level is never exceeded (the system rated capacity), the load cell is capable of having loads applied to it and removed from it a practically infinite number of times without failing. The amount of weight that would cause that stress level to be exceeded will vary from load cell to load cell although it will never be lower than the load rating of the crane scale. This is one great reason why you can rely on Eilon Engineering to provide you with a reliable measurement system that can withstand the test of time.