The plastic bags can be made of several materials, such as OPP、CPP、PP、PE、PVA、EVA、etc. They have different characters.

OPP BAG：

Feature：hard，the shape will not change after being pulled. Can not be pulled. Jointing edges. Max length is 640 mm。L:1.28m，W:0.6m.

Advantage：well transparency

Shortcoming：edge is not very firm

PP BAG：(Polypropylene)

Feature：hard, but not hard then OPP，the shape will change after pull. Joint at bottom or edges. Transparency is not as good as OPP.

PE BAG：(Polyethylene)

Feature：Contains formalin，Transparency is not very good.

HDPE：High density polyethylene: Brickle.

LDPE：Low density polyethylene: soft

PVA BAG：

Feature：environment un-polluted material，can melt in water.

Advantage，soft，well transparency.

CPP BAG：

Feature：Does not contain formalin, transparency is better than PE, it will become longer after being pulled. Transparency is as good as PP，as soft as PE.