This innovative and award winning magnetic construction system allows builders to create rigid cubical structures, adding stability to construction and increasing design possibilities. Provides endless opportunities to learn about magnetism, basic geometry, physics, architecture and engineering. Set of 300 includes 150 magnetic bars (2-1/4 L inches) in 7 different colors, 90 iron balls, 70 tripod connectors, a durable plastic storage case and a teacher's guide. Ages 3 and up.