PWZ1000: Features: -Aquarium substrate. -Natural gravel. -100% Acrylic coating. -Will not alter the chemistry of your aquarium water. -Non toxic. -Colorfast. -Package 2 / 15 lbs bags per case. -Made in United States. Recommended Use: -Fresh and saltwater aquariums, ponds, terrariums, gardens, potted plants, vases, ash trays, crafts and hobbies, architectural surfaces and landscaping designs. Specifications: -Grain size: 19-38.1mm. -Dimensions: 22 H x 12 W x 2 D.