This term is used (accurately) to describe products outside of the realm of packaging. In packaging, however, the term “poly tubing” almost always refers to a roll of flat plastic tubing made from low density polyethylene (LDPE). As raw materials engineering has advanced, this now includes linear low density polyethylene (LLDPE) and can also be used to describe bags made from medium density polyethylene (MDPE), high density polyethylene (HDPE) or all of the above.