MATERIAL: * Inside: Poly * Outside: Cast nylon. * Maximum Temperature: Withstands up to 149 FSEAL TIME: * The length of time bags will hold the vacuum seal depends on what is packaged: * Meat/fish (no bones) - 20 days if refrigerated 6 months if frozen * Meat with bones - Can't guarantee as bones may puncture the bag. * Dry goods/electronics- 30+ days.MISCELLANEOUS: * Not Compatible: Home vacuum sealers. They are not powerful enough to fully seal this item. * Not for use in boiling water. * BPA Free * Can be frozen.