Stack Building Blocks are one of the most popular playground equipments for kids around. In fact, children everywhere around the world universally love Stack Building Blocks. Sii brings you this amazingly high quality set of building blocks to have for your preschool, primary school, or your own backyard. Kids are going to have many fun building new things with Stack Building Blocks along with their friends. This set of building blocks is made from safe plastic, which means you do not have to worry about kids' health with this one.