Good quality plastic and withstands rough handling! We bought it when my son was 3.5 years old and we have been playing with it ever since. It is interesting because you can create infinite combinations with the included pieces, so you can build something different every time. It also includes a manual with examples of how to assemble it. It can hold the classic marbles - balls, and if you lose the ones it comes with, they are sold separately in mesh bags. We bought the next model with the elevator the following year and expanded the marble run for more playtime.