The Harvest Keeper® Air Out® Oxygen Absorbers are made with specific powdered irons that make oxidation happen. These packets will absorb oxygen in a confined space. Lack of oxygen may inhibit growth of molds, mildew and aerobic bacteria. Air OUT® is food safe and does not release any harmful gases or toxic elements. You can expect a better shelf life for your products and they will help retain flavors and aromas. The 50 cc pack size (1.5 in x 1.5 in x .125 in) will absorb 50 cubic centimeters of oxygen in a confined space. The 100 cc pack size (2 in x 1.75 in x .125 in) will absorb 100 cubic centimeters of oxygen in a confined space. Similarly, the 500 cc pack size (3.25 in x 2.875 in x .125 in) will absorb 500 cubic centimeters of oxygen in a confined space.