Zip-Bags 'YingYang' . This Zip-Bag protects against flour and dust. Nothing goes missing by the quick lock. This Zip-bags, or also known as Zipper-bags, are suitable for storage and package of food products. This bags are made of PE-LD (Low Density), or named as LDPE. Fundamental is PE-LD more flexible as PE-HD (High densitiy) or PP (Polypropylen). The tensile strength at 20°C is nearly 10 N/mm².