This boxed set of high-quality prisms is made from clear acrylic sheet with polished sides. Set consists of six prisms: one rectangular 75 x 50 x 15 mm block, one semi-circle 90 mm base x 15 mm thick, one equilateral 75 mm sides x 15 mm thick, one double convex 90 mm L x 23 mm center lens, and 2 concave 90 mm L x 10 mm center lenses. a variety of shapes and an activity guide. Measures 10" x 8" x 2".