These Citonella sticks are reliable and worth the price. I had some from 10 years ago so I decided to burn them and they were still burnable. These sticks are thick and last for at least two hours and minutes more. They burn slow and the smoke does rid the mosquitoes. Sorry I can't tell you the perimeter however I use one stick and move the stick as I move around my garden just to be on safe side. After being bitten by mosquitoes, my skin swells up puffy red therefore it is essential I keep these Citronella sticks around when I am outside early a m and late evening after 6 p m. Additionally, after the rain wets the stick then allowing the stick to dry; the stick still lights up and burns down properly. These sticks are effective while I am fresh water fishing, on a horse trail ride, or whatever event is happening. I truly depend on the Citronella stick for an enjoyable day while out. Buy them: you will only thank yourself.