1000 Series wipe have the best abrasion Chemical resistant and the fiber is thicker not easy to break ,less particle , so can wash more times to reach high cleanliness ,so the fiber of 140g is thicker than  120g. 

As we know the cleanliness is depend on the how many times washed, then you will ask why 120g wipe also have class 100, it is in order to meet the market requirement , so we make this type .120g  sell more in Southeast Asian countries and more use in hard disk.

And many customer will use the wipe with IPA to reach better cleaing effect.