The Hayabusa Cobra Reflex Bag sharpens your reflexes with a rapid rebound spring that helps you develop punch speed accuracy and defensive maneuverability. The heavyweight base keeps the cobra bag securely in place as it swings and recoils up to 90? for honing rhythm and head movement. Perfect for all martial artists and fighters of all skill levels. Features: High tension steel spring swings and recoils at rapid speed Ultra sturdy base tank holds water/sand for heavyweight stability Perfect density rebound ball delivers excellent feedback with a satisfying pop on impact. Easily adjustable height simulates different opponent sizes Compact design for a small footprint in any home gym