Just tie the line to a tree or other object and set the meter to zero. As you walk, the meter measures and indicates the length of line pulled out, giving you the distance you?ve traveled. Your hands are free for other tasks. After use, simply break and discard the disposable line, reset the counter, and you?re ready to measure again! High-impact plastic housing with belt loops to fit belts up to 2-1/4? wide. Precision counting meter resets to zero. Easily replaceable spools of line. Measuring capacity (without resetting meter): Feet to 99,999, yards to 9,999.9, meters to 9,999.9. Accuracy: within ?0.2%.