Blade Board, S-Board, J-Board, Skateboard, Blade Board, J-Board, S-Board, Caster Board, Balance Board No defects. A unique feature of the J-Board is that you can have fun while playing and developing a dynamic sense of balance. Children aged 6 to 12 are in the "Golden Age" when their physical abilities rapidly develop, and it's a time when they can improve their motor skills through play.