Hydrostone Plaster for Scenery Dioramas and Casting, Creates Super Hard Castings With Great Detail Quick setting, lightweight white / light gray plaster in water resistant resealable bag. Ideal for patterns, figurines, commercial casts, and sculpture. It is not for making outer or mother molds, and it is not recommended for outdoor use. Full strength Hydrostone gypsum plaster, not cut with cheap plaster fillers Designed for strength and casting detail. Hydrostone is 40% to 50% harder than casting plaster and works much like plaster in mixing, pouring, and setting. Accepts liquid or crystal pigment colors and stains Hydrostone quick setting white / light gray casting plaster. Full strength gypsum plaster is not cut with cheap plaster fillers like the popular brand! Designed for strength and casting detail. Accepts liquid or crystal pigment colors and stains. Packed in water tight resealable bag, not a leaky carton. Great for model railroads scenery, gaming castings, and school project dioramas. Not for body casting.