Totally free-standing, the Ringside Cobra Reflex Bag can be conveniently placed where ever you need it, whether it's in the gym, home workout area, or even your office. The industrial grade, rapid-rebound spring guarantees a lightning fast return of the bag every time, so you can build speed, hand-eye coordination, strength and conditioning. The foam filled punching bag requires no inflation and is ready to use right out of the box. Product Features Sturdy steel frame Rapid-rebound spring Adjustable 5' to 7' height Base can be filled with 140 lbs. of water or sand