The DT value is physically defined as the ball force in kp (kilopond) that is required to press the string bed by 1 cm for a short time (ball strike). Internat. Unit kp/cm, Newton/mm

The DT value defines the playing characteristics power and control. A soft-strung racket with a low DT value generates more power through ball acceleration. A hard strung racket with a higher DT value provides more control and thus playing precision. Every player has his optimal DT value. He can determine this himself with the ERT 300 during training and through his playing experience.

The DT value is influenced by the following factors: stringing weight (refrence tension set on the maschine), accuracy and condition of the stringing machine, technique of the stringer, material and diameter of the string, head size and stringing pattern of the racquet