LavaLock brand thermometers are simply the best. The highest quality BBQ smoker thermometers on the market. Fits / for Oklahoma Joe's Highland and Longhorn as well as other cookers using 1/2" NPT hole (approx 3/4" hole if using a tape measure). Installation note, use a wrench on the stem nut to tighten (do not grab thermometer face). While these thermometers are adjustable, be sure proper calibration methods are used (contact us). They carry a warranty against defect and are extremely accurate and heavy duty. Installation methods vary. Installation is simple into any existing 1/2" NPT thread fitting or bung, or you can tap a 1/2" npt hole, or purchase a thermo install kit, thermo nut, or one of our weldable bungs if necessary for your application.