Bigger opening with a 4-inch diameter for filling or emptying Dimensions: 11 inches in width, 14 inches in length, and 9.5 inches in height Contains up to 50 pounds of water. Easily fill with water in seconds by scooping it up onto the swim deck. Two handles provided for convenient grip and transportation. You can fill the sac with various materials! Water, rocks, sand, and metal slugs are all suitable options. Adjust your wake for smooth riding or surfing. The sturdiest and strongest fillable weight available in the market. 2 pack of 50 lbs fillable weights.