This thermometer is made to be installed into the lid of your Holland Grill as a replacement or if your grill did not come with one already installed. It will tell you the approximate inside grill temperature and give you a good idea when your grill is preheated and ready to go. It has both Fahrenheit and Celsius temperature readings. You will need to drill 3 holes in your grill even if you are replacing an older lid thermometer that already had one hole in the lid, you will still need to drill 3 holes.