Ezi caphu ze-polypropylene zineempawu ezigqwesileyo kwaye zinike ukungavisisani kweekhemikhali ezifanelekileyo kubandakanya i-acids, ilokishi, ialkalis, iimveliso ezizezinye, kunye neoyile yasezindlu. I-Polypropylene Hole Caps iyaziwa ngamandla amahle, ukusebenza ngeendleko, kunye nokufakwa kwexabiso.