Vacuum packing is one of the best ways to store perishable food. You can Vacuum pack either fresh or frozen, as it removes the air that causes oxidation and this allows your food to stay fresher for longer. The ZipVac™ system uses reusable, resealable bags of various sizes and a simple manual pump to remove the air.Its unique one way valve ensures what you draw out through the pump stays out. The bags have a sturdy 3 ply construction and will with stand use in the microwave and boiling water.