The Petrol PWSB-2 Water/Sand Bag is lightweight (barely 1 lb (0.48 kg)) and folds nearly flat when it's empty, but it can hold 0.9 gal (3 liters) of water or sand in its interior PVC container--making it hefty enough for stabilizing a light stand or tripod on location. Empty it out and it's ready to travel to your next location.
Refillable water or sand bag weight