Approx 3 in diameter round with matching stretchy string for easy hanging. What is the product shelf life? Shelf life is two years, if stored in a cool dry place. Do you use recycled paperboard for your fresheners? Yes, our custom air freshener board is made up of 25% recycled materials. How long does the smell last? Once taken completely out of the wrapper, the personalized air freshener should provide a pleasant aroma for at least 10-15 days in mild climates. Expect aroma longevity to decrease in hot climates. If only a portion of the wrapper is taken off the freshener, aroma longevity will be greatly increased.