When you get your six and go to fill them with store bought "citronella lamp oil" (to keep the bugs away), you will find that 6 of them can burn a 50 bucks worth of this fancy stuff in a weekend.

If you prefer to not burn your money, look at this stuff:

http://www.newdirectionsaromatics.com/citronella-java-essential-oil-p-218.html

What it is is 100% citronella oil. They store bought stuff is mostly kerosene, with a small amount of this stuff added.

I add a couple of ounces of 100% Citronella Java to each gallon of pump bought kerosene, making my cost under 4 bucks a gallon for my "citronella lamp oil" rather than well over 10 bucks a gallon for the store bought stuff.