THE RETENSER PRO

World's 1st Tension Adjusting Device Adjust the tension of the center 4 or 6 main strings by +-2.25, +-4.5 or +-7 lbs. Power & Control available to the player will vary accordingly. Minimal effect on racquet Weight, Balance or Swing Weight. [Click here for more detailed info on Retenser](https://tennissensei.com/retenser.html)