Rubber Ball Thorn Fit Lacrosse ball double black Duoball Thorn Fit is used to increase the mobility of the body. The model is designed based on the biomechanics of the spine for the purpose effective and safe impact on body posture and reducing muscle tension. Rubber surface reduces sliding of balls. Small size. Special connector between two balls will take for even better fit and comfort, which can be appreciated during massage of delicate areas of the neck and spine. Technical data :· Diameter: 63 mm· Width: 126 mm· Weight: 324 g· Color: black