Size: 4 oz. Why is GreenHead the best insect repellent you can buy? Not only is it more effective, it's safer too. GreenHead contains 30% of the EPA approved active ingredient for repelling insects which is much more than the competition. So, in the same size bottle, you get up to four times as much "repellent" and less "other stuff". The "other stuff" is important too- Instead of being mixed with alcohol (like most other popular brands), we use water instead of alcohol, which not only makes it safer to use, but much more effective and longer lasting! Most insect repellents work when you first put them on, but they start to evaporate immediately, losing effectiveness in just a few minutes. DAK Pharmaceuticals has really shaken up the industry by replacing the alcohol with water which is not only safer, but makes it work better. Because water does not evaporate as quickly as alcohol, dermal absorption is reduced and more "repellent" is left on your skin! Thus, the need to frequently reapply the repellent is greatly reduced and it works much longer.