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. The gauge will also give you an average of up to the last 10 readings. Switch from ounces to grams with the push of a button. The fully adjustable rod works on any firearm. This is the perfect tool for target shooters, silhouette shooters, gunsmiths, hunters, or anyone who wants to adjust their trigger pull weight accurately and easily. Works with single 9V battery (not included). NOTE: Kindly refer the user manual before usage of the product..