Premium Quality Car Air Fresheners Made in the USA Hang Freely to Avoid Stain or Damage All of Bomb Freshener’s premium quality air fresheners come with an attached elastic string in a clear plastic wrapper. Shelf life of the fresheners is two years, if kept in a cool dry place. Once opened, with the wrapper completely removed, expect to enjoy two to three weeks of pleasant aroma. Avoiding high automobile interior temperatures as well as prolonged window open time, can greatly increase the longevity of any air freshener.