ENSURES SAFE AND ACCURATE TRIGGER ADJUSTMENTS Works with almost any rifle, shotgun or handgun. Specifications: Measuring Range: 1oz - 12lbs / 2.8g - 5.4kg Resolution: 0 - 5lbs: ± .1oz 5 - 12lbs: ± .5oz 0 - 2.2kg: ± 2g 2.2 - 5.4kg: ± 10g Lyman’s revolutionary Digital Trigger Pull Gauge is designed to be the fastest and most accurate trigger pull gauge available. The state-of-the-art strain gauge technology allows for accuracy of 1/10 ounce/2 grams. The gauge will read to a maximum 12lb/5.4kg and features a large, easy-to-read LCD display. To operate, simply press the ready button, hook the roller around the trigger of your firearm and pull until the trigger releases. (Make sure firearm is not loaded.) The gauge will display and hold the exact trigger pull weight. For a new reading, just press the ready button and repeat.