This is Woodland Scenics' 1/2 Gallon light weight Hydrocal.
FEATURES:

Specially formulated for terrain model builders.
Half the weight of Hydrocal and goes twice as far.
It's the tough, quick setting product you will prefer!
Use it for casting rocks, creating hard shell scenery, filling in
around castings and as an adhesive.
Leaves a smooth finish.
May be used on Plaster Cloth for making strong hard surfaces.
May be tinted with Woodland Scenics Earth Colors (liquid pigments).
Instructions are listed on the side of the package.
YOU WILL RECEIVE:

One Carton of light weight Hydrocal
REQUIREMENTS:

Mixing Utensils and Bowls
SPECIFICATIONS:

Volume: 1/2 gal