The Open Bricks base plate 20x20 black includes 4 base plates and offers double the fun, as it can be built on both sides. The Open Bricks base plate is compatible with all traditional building block manufacturers, allowing for the construction of large castles, houses, and much more. Let your imagination run wild and discover the versatile world of Open Bricks base plates. Recommended age: From 4 years - 4 base plates each 20 x 20 studs (16 x 16 cm) - buildable on both sides - 100% compatible with all traditional building block manufacturers Warning: Not suitable for children under 36 months.