The Newly Designed SPK2 Folding Pocket Thermometer Is Great For Taking Quick Air Temperatures. It Fits Directly In Your Pocket So You'Re Ready For Common Temperature Checking. The Folding Rod Has A Hanging Hook So You Can Easily Hang It In A Duct or On A Grille. The Large Display Shows Min/Max/Hold, Has Measurements In Both Fahrenheit and Celsius, and Has A Low Battery Indicator. It Also Quickly Calculates T1-T2, As Well As Features An Auto Power Off Function To Save Battery Power On It's Already Phenomenal 8,000 Hours Of Battery Life On One Single Aa Battery!