The ERT 300 quickly and accurately measures the dynamic tension of the string bed of a strung racket. This DT value determines how well you get on with your racket.

The DT value defines the power and control of your game. A softly strung racket with a low DT reading generates more power by ball acceleration. A firmly strung racquet with a higher DT reading ensures better control and thus precision. Each player has his or her own optimum DT value. He or she can determine this value by using the ERT 300 when training and by means of playing experience.

[Defined physically, the DT value is the ball power in kp (kilopond) that is required to depress the string bed by 1 cm for a short period of time (ball impact). International units: kp/cm, Newton /mm]