TECHNIC PIECES BULK INCLUDES-The sets include all the pieces shown as the product page displayed. There are 591 pieces include gears, pins, axles, frame Liftarms, beams connector in different sizes. MULTIPLE PURPOSES- It is a great replacement or choice for project, a substitute for model assembly, perfect for creating your own model with your regular building blocks, etc. LARGE COMPATIBIITY-The set is compatible with the major brand bricks. It can be used for th building bricks model, such as the cars, robots, engineering cranes, and more other brick models. GIFTS-An awesome gift for someone who are fond of model building, suitable for birthday gifts, Christmas gifts, etc. MATRIAL-Pastic, it is simple to be assmbled, sturdy in quality. 591PCS Technic Parts and Pieces Bulk Compatible with Major Brand Bricks, Technic Beams and Pins Connectors Set, Technic Replacement Parts- Connectors, Axles, Liftarm, Pins