The Seven layers are extruded together to make them more versatile. During anti-pressure testing, it can withstand -25mpa atmospheric pressure. It may undergo dramatic changes in temperature. The elevated temperature could exceed 110C and All microholes are film-covered and the vacuum rate was as high as 99%. Made with BPA super ductile materials, overlapping structure output, cut off air invasion are not included in the SGS certification, so that the items in the bag can be negative oxygen for a long time in the atmosphere of low pressure. Holding calm, anti-mildew, anti-humidity, anti-insect. It can be frozen, steamed, refrigerated, suitable for refrigerator, microwave oven, microwave oven,