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]