3 years and up. This set of Translucent Sensory Gem Cubes features 20 acrylic cubes perfect for color mixing, stacking, and balancing. Place cubes on a light panel or hold them in front of a window to create colorful shadows and watch colors dance. These colorful manipulatives are appealing for children to handle, which makes them an excellent resource for open-ended, sensory play. The high-quality, solid acrylic cubes are easy to wash and are designed to last for years of classroom or center use. Set also comes with a drawstring bag for easy storage and travel. Clean with warm water and mild soap. Each cube measures 1".