It is a plastic with good toughness. allow a little bit of air to go in and out but does not allow water to seep through Makes it able to keep food fresh as well It is also able to withstand chemicals as well. This makes it possible to safely contain slightly abrasive food. Resistant to cold more than -20 degrees (PP special texture for freezing) can withstand heat up to the boiling point of water. And can bring this type of container that put food Can go into the microwave oven to warm up food. (Microwavable) suitable for storing frozen food, fresh food, all kinds of processed food The test method is PP by normal burning, easily ignited, white smoke.