Plastic and rubber ball mounted on highly resistant ropes and elastics. Helps keeping horses who need stimulation entertained, and to break vices (weaving, cribbing, or wind-sucking). 
To be fastened on rings to the ceiling of the stall, in opposite corners or to the doorframe, taking care that the ball does not touch the wall.
Suggestion: stick some carrots between the elastics, and your horse will get to the ball easier!