Want to have more options to loading your Ultimate Sandbag? You can choose to add instability or weight by using additional Ultimate Sandbag Water Filler Bags. Great for travel and allows for easy loading and unloading of the water. Our Water Fillers allow for increased instability in your training. All our Ultimate Sandbag Fillers are available to purchase separately and do not come with outer shells. Our Advanced Water Fillers currently come in two sizes so that you can quickly and conveniently change the weight of your Ultimate Sandbag. With any purchase of our DVRT Advanced Water Filler Bags you will also receive download links to our Water Bag Manual containing 10 workouts!