To recalibrate Tel-Tru Dial Thermometers first read the information on Testing the Accuracy of your Thermometer. Also you may refer to our Pocket/Laboratory/Testing/Spot Checking or Industrial dial Thermometers product manuals. The thermometer must have a recal/reset feature (Ex: GT300R, AA375R, LT225R, etc) Or see our manuals: https://www.teltru.com/wp-content/uploads/01204003.pdf or https://www.teltru.com/wp-content/uploads/01204001.pdf



