These self-adhesive reusable temperature labels provide a safe, accurate, easy-to-read means for monitoring temperatures. Indicating strips use liquid crystal technology to display the current temperature at an economical cost. The strip will turns a green color when ambient temperature is reached. Shelf life: 1 year after date of purchase. Each style covers a wide range of temperatures, for use in many different application non-toxic/non-hazardous temperature measuring alternative. Easy to read and unbreakable.