The 70-piece Quadrilla Melody Basic Set includes 50 pieces of Baltic birch rails and rubber wood blocks plus 5 tones, certain to appeal to a budding builder who also likes to discover melodies while constructing marble runs. Twenty marbles fill out the set and stay put in two catchall trays once they finish their breathtaking, melodic trip down the rails. An instruction booklet provides layout ideas to get started. For kids age 4.