Before using the Ultimate Sandbag I just thought a sandbag was a sandbag was a sandbag. The Ultimate Sandbag is a completely different animal, and this smallish size also surprised me with it's challenging nature! I'm used to heavy kettlebells, but just 25lbs in this bag got my attention! I tend to use it for higher rep, endurance workouts, but the ever-moving, shifting weight ensures things never get boring! Having the Power Bag and the Strength Bag together has allowed me to create challenging, mind-bending workouts for myself and most clients. (They're also very easy on floors... so the Ultimate Sandbag is a great choice for at-home, indoor workouts)