The Hayabusa Cobra Reflex Bag sharpens your reflexes with a quick spring that helps you develop strike speed, accuracy and defensive maneuvering. The heavy base keeps the cobra bag securely in place while it swings and unwinds up to 90° to perfect your rhythm and head movement. Ideal for all boxers, martial artists and fighters of all skill levels. High tension steel spring swings and unwinds at high speed Extra strong base tank holds water/sand for heavy weight stability Ball with perfect bounce density provides excellent feedback with satisfying pop on impact Easily adjustable height simulates different sized opponents Compact design for small footprint in any home gym Designed for use with boxing gloves or just hand warmers. Adjustable height: 156-180 cm Bouncing ball size: 18.5 x 25 cm Diameter: 50 cm, height: 37 cm