All our waist harnesses are equipped with a Kidney neoprene belt. Our stickflex body control belt is designed specially for windsurfers/kitesurfers with a tighter fit, less movement and greater control. It is well known in various other sports that a kidney belt supports your kidney¹s. This makes you less tired and keeps you healthier. The wide neoprene belt is specially designed using a unique combination of neoprene & ski material for a perfect fit and additional warmth.