Swipimelo swa vulawuri bya khwalithi ya PET strap (polyester strap) switiyisisa matirhelo lawa yanga cincekiki xikan’we na vuhlayiseki bya ndzhwalo. Hikuya hi swihlawulekisi swa ASTM D3950, ku kamberiwa ka khwalithi swifanele ku tiyisisa matimba ya tensile, elongation, dimensional accuracy, na heat seal strength . Nkongomiso lowu wu hlamusela swipimelo swa nkoka swa vulawuri bya khwalithi, tiphrothokholi to kambela, na leswi vaxavi va faneleke ku swi languta loko va tiyisisa khwalithi ya PET strap.