A value of "1 - lowest elasticity" indicates filaments that are very strong and stiff. These materials retain their shape and put up a lot of resistance when trying to bend. If a large enough force is applied to them, they will not bend, but rather crack or break. Typical representatives of this category are commonly used materials such as PLA, PETG, ABS or ASA. They are used for printing models and parts where it is desirable that they do not deform under load. For example, structural components, electronics enclosures, architectural models or decorative items that are intended to be dimensionally stable. The number 1 in this designation represents the lowest grade on the flexibility scale, where higher numbers would indicate materials with progressively increasing flexibility.