Precast Stone Molds 711/1 Precast Brick Stone Molds You are purchasing 18 section urethane rubber mold designed for casting plaster, concrete and polymer concrete. The Concrete Stone Mold size  3 SQ.FT.(0.28m2) approximate, measurements are 24 X 16.5 X 1 (61cm X 42cm X 2.5cm). Approx. size of each section 7 1/2 X 2 1/4X 1/2" (19cm X 6cm X 1.5cm).