The Apex Speed Bag merges the traditional benefits of the sport’s past with the modern materials and intricate detailing of today. This proven training tool will develop speed, timing, strength and endurance. A note regarding bladders: Latex rubber is a porous material and air will escape with each use; thus, the bag may require light inflation every couple of days. Although frequent inflation may be required, latex bladders far outperform other bladder options. Butyl rubber bladders are heavy and slow. Plastic bladders are oblong and don’t provide a consistent rebound.