Our hardwood blocks are so durable, they’re backed by a 50-year guarantee! Each block is made of solid hardrock maple, kiln-dried, sanded and beveled for perfect building balance—ensuring that they’re the highest quality you can buy! They’re guaranteed classroom-tough and will stand up to year after year of rough play. And if any block breaks or splinters within 50 years of the date of purchase, we will replace it at no charge! Plus, as children design and build, they practice problem solving, develop perception skills and explore basic math and science. Each block is precisely related in size to the basic unit block (5 1/2"l x 2 3/4"w x 1 3/8"h) for a comfortable series of relationships that makes it easy to create and learn. Set includes 318 blocks in 25 shapes. Accessories sold separately.