The powerbag is a weight-filled bag. The bag is soft to touch, with strong handles on each end.
Powerbag training, unlike traditional weight training equipment, utilises the movement and instability within the power bag itself to create an element of unpredictability during exercise. This forces the stabilising muscles to accommodate the shifts in weight during the course of the movement.
This helps to make Power bag based training more effective than many training approaches towards improving performance in real world situations, be they sporting or otherwise.