Robby's Bowling Accessories. This 9 by 4 back wrist support keeps the forearm straight and extends over the knuckles for better finger and wrist positioning. Your hand stays behind the ball, giving more forward revs. Develop your own technique with this proven control system. By stroking up on the side of the ball, you gain more side revolutions and increased angle entry. The finger strap can wrap two, three, or all four fingers to keep them comfortably aligned with the metal support. A metal feature in the palm adds even more support.Right or left hand available in petite, small, medium, large and extra large.