They do arrive empty so i recommend purchasing children's sandbox sand from home depot or lowes, also just to be safe it's a good to pour the sand into a gallon ziplock bag and double-bag it before stuffing it into the saddlebags

I filled gallon-size zip-closure plastic food bags with dry sand to stuff into these bags, just as an extra precaution against leakage

Great bags, used gallon ziplock bags inside filled with sand, they work great for holding down my c-stands

Fill a 1-gallon freezer bag with 10 cups of sand (more than 10 cups seemed to be too much for the sandbag pocket to handle)