In praise of ... the double end bag

The double end bag or floor to ceiling bag is one of the most under-rated pieces of equipment in the boxing gym.  It is round football size bag that is attached to the floor and the ceiling by two pieces of elastic or bungee.  The elastic causes the bag to swing violently when you hit it, making it hard to hit the next time around.  So it helps you in your hand eye co-ordination and swing can be seen as an opponent's punch, meaning you can practicing your slipping and weaving skills at the same time.  So for me it is my favorite piece of boxing gym equipment.  Here is a perfect demonstration of it by Tim Bradley.