Open to two or more interpretations; or of uncertain nature or significance; or (often) intended to mislead. Synonyms: ambiguous; equivocal. Context examples:
Many of the polypropylene sleeves are less than 2 mil. Many of the sleeves being sold on the internet and by hobby and comic shops are very flimsy and range from .5 mil to 2 mil. The majority of commercially-available polypropylene sleeves are 1 to 1.5 mil. Our polyethylene sleeves are 2 mil and 3 mil, respectively. In more chemistry-speak, propylene (CH3CH:CH2) is is a sub-stratum of ethylene. Ethylene is the purest form of the base chemical and thus the purer better of the two.
Hard plastics like polystyrene and poly(methyl methacrylate), are used below their glass transition temperatures; that is in their glassy state. Their Tg's are well above room temperature, both at around 100 o C. Rubber elastomers like polyisoprene and polyisobutylene, are used above their Tg's, that is, in the rubbery state, where they are soft and flexible.