Abstract: An exercise device having a water-tight, interior compartment into which a destabilizing liquid can be added to fill the device to a desired weight, such as by indicated on weight marks provided on an exterior surface of the exercise device. The device is capable of being filled with the destabilizing liquid via a water port of the device, which may be releasably securable to a water hose or faucet. The destabilizing liquid filling the interior compartment of the exercise device provides resistance to muscular movement and provides destabilization of the device as an aid in improving a user's balance and coordination. Handles and/or at least one protruding knob are provided on the exterior surface of the exercise device, and/or padded straps are provided on the exterior surface of the exercise device for attaching the device to the user's limbs or back. One side of the device may be flattened and padded to increase comfort for the user when the device is attached to the user's body.