The classic screw and nut will accompany children throughout their lives. Construction sets provide children with space for free play, allowing the assembly of many variable units, thereby developing motor skills, as well as spatial imagination, creativity, and patience. They can be used repeatedly and often for many years. For younger children, they help develop color and shape perception and fine motor skills, while for older children, they can aid in understanding basic mathematical or physical concepts. The box contains a complete set of 280 pieces, including 2 gears with a chain of 50 links.