_x000D_ _x000D_ _x000D_ _x000D_ 1. Feature:Keep your reference tension in check with the tension calibrator stringer tools _x000D_ 2. A must have for proper stringing machine maintenance. _x000D_ 3. A racket that has just been put on the line or used for a period of time, usually the midpoint value of the beat value measured by the pressure gauge is too small, and the pressure value around the beat tends to be more pounds, compared to the horizontal line, vertical The line's beat value tends to be more pounds. _x000D_ _x000D_ specification: _x000D_ 1. 0-42lbs _x000D_ 2. Know when it is time to restring _x000D_ 3. Easy to operate _x000D_ 4. Model:AC-SM200 _x000D_ colour: black _x000D_ Material: PVC _x000D_ _x000D_ Package Contents: _x000D_ 1 x Tension Calibrator _x000D_ _x000D_ Only the above package content, other products are not included. _x000D_ Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_