Emceepack manufactures the linkable products from PP, LDPE and HDPE. When you click on the link of the polymer types, you will find an explanation of each type from wikipedia.org

Polymer TypesExamples of applicationsSymbol
Polyethylene TerephthalateSoda (fizzy) drink and water bottles. Salad trays.
High Density PolyethylenePlant sleeves, milk bottles, bleach, cleaners and most shampoo bottles.
Polyvinyl ChloridePipes, fittings, window and door frames (rigid PVC).Thermal insulation (PVC foam) and automotive parts.
Low Density PolyethyleneCarrier bags, bin liners and packaging films.
Cast Polypropylene (CPP)Transport packaging like plant sleeves and flower sleeves, magazine wraps, deli wraps, margarine tubs, microwaveable meal trays, also produced as fibres and filaments for carpets, wall coverings and vehicle upholstery.
Oriented Polypropylene (OPP or BOPP)Display (show) packaging for the flowers & plants, crystal clear packaging for gift cards, deli wraps, cigarette wraps.
PolystyreneYoghurt pots, foam hamburger boxes and egg cartons, plastic cutlery, protective packaging for electronic goods and toys. Insulating material in the building and construction industry.