Actually, a "SLIP BAG" and a "DOUBLE-END BAG" are two entirely different pieces of equipment.
A Double-End Bag is an inflated ball with bungee cords attached to the top and bottom, anchored to ceiling and floor.
http://www.ringside.com/store/prodin...tem=2&mitem=11
A Slip Bag is a small weighted bag similar to a Speed Bag, that is suspended from the ceiling and swung. It is also referred to as a Maize Ball
http://www.ringside.com/store/prodin...m=87&mitem=134
Khun Kao