Sandbag training can provide a non‎-conventional method for building muscle‎,‎ boosting overall strength and burning gobs of fat and calories‎.‎ The secret to sandbag training lies in the moving and shifting of the load within the sandbag‎.‎ Due to the nature of sandbags‎,‎ more muscles must work harder to compensate for the instability of the weight‎.‎ More muscles worked equals more calories burned and greater gains in strength both in the major muscle groups as well as minor muscle groups and the core‎.‎ Sandbag training can provide a much needed break from a standard weight lifting routine while keeping the body challenged and on its toes for maximum performance‎.‎ If you are looking for something challenging and something different‎;‎ sandbag training may be the way to reach a whole new level of strength and fitness‎.‎ The Perform Better Ultimate sandbag is one of the most versatile and challenging exercise tools available‎.‎ With adjustable resistance and ease of use‎,‎ the Ultimate sandbag is sure to become one of your “go‎-to” pieces of training equipment‎.‎ Heavy‎-Duty Outer Shell‎.‎ The Ultimate sandbag features an outer shell that contains inner bags‎.‎ The heavy‎-duty outer shell uses both zippers as well as buttons to enclose the inner bags‎.‎ This outer shell keeps the weight of the inner bags secure‎,‎ and keeps the sand where it belongs‎-inside the bag‎.‎ Inner Filler Bags‎.‎ Contained inside the secure outer shell are the inner bags that get filled with sand‎.‎ The amount of sand in the bags can be easily and quickly adjusted to add or remove resistance from your conditioning workout‎.‎ The use of a multilayer bag system keeps sand secure and prevents mess‎.‎