https://www.avient.com/idea/what-s-difference-fillers-reinforcements
Long-glass fiber (LGF), which can be longer than one-half inch, can be tougher and more impact resistant (especially in cold temperatures) and have more tensile strength (ability to stretch without breaking) than a comparable SGF composite.
Because an LGF’s advantage comes from its longer length, it is important to avoid breaking the fiber during processing.
LGF-reinforced plastic can be molded in standard equipment, but manufacturers should follow recommended processing guidelines, such as those described in the of this e-book.