Guidecraft Jr. Rainbow Blocks: 40 Piece Set - Kids Learning & Educational Toys, Stacking Blocks Durable hardwood frames with vibrantly colored insets Educational Focus: Hand-eye coordination, visual perception, color exploration or light table activities Material: Hardwood frames with primary colored, transparent acrylic windows One third smaller than standard unit block measurements Set includes 40 assorted shapes of solid wood frames with inset colored acrylic windows for ages 2+