Package Deal! Tire Durometer & Tread Depth Gauge - with silver case and two pouches. Durometer Racing Tire Hardness Tester Tire hardness has a huge affect on your car's performance. A tire too hard won't bite and a tire too soft may wear quickly or even ball up. Also tire hardness changes during its life cycle. To run your best you must keep track of all your tire's hardnesses. This easy-to-use tool will help you do just that - quickly, accurately & easily. Reads from 0-100 points (Shore 'A' scale) Straight edge on base to 'rock' durometer for more consistent results. Non-slip coating for better grip. Calibration test block included. Dial can be 'Zeroed' For the most consistent results rock the durometer from angled back past straight up to angled forward. The pointer will move up to the highest (true) reading, then back down. Record the highest reading reached. Tread Depth Gauge Super accurate, easy to read, easy to use. Calibrated in 1/32" Accurate to 1/128" (less than .010"!)