- Ideal Starter Set for an introduction to GraviTrax - Starter Set with a lower price point - Can be combined with all Junior Starter Sets, Extensions, and Elements The GraviTrax Junior Starter Set My start and run offers boys and girls an ideal introduction to the GraviTrax Junior universe. Children aged 3 and up build their own marble run world. All components are made of wood-bioplastic. The Starter Set can be expanded with elements, other Junior Starter Sets, or Extension Sets. GraviTrax Junior is an interactive marble run system for children aged 3 and up. Children can build their own marble run world to their heart's content and decorate it with all sorts of different themed sets. Creative building and fun are combined. - Ideal Starter Set for an introduction to GraviTrax - Starter Set with a lower price point - Can be combined with all Junior Starter Sets, Extensions, and Elements The GraviTrax Junior Starter Set My start and run offers boys and girls an ideal introduction to the GraviTrax Junior universe. Children aged 3 and up build their own marble run world. All components are made of wood-bioplastic. The Starter Set can be expanded with elements, other Junior Starter Sets, or Extension Sets. GraviTrax Junior is an interactive marble run system for children aged 3 and up. Children can build their own marble run world to their heart's content and decorate it with all sorts of different themed sets. Creative building and fun are combined. 32 parts: 3 base plates, 2 marbles, 16 height blocks, 2 straight blocks, 2 slopes, 2 large curves, 2 small curves, 1 Start, 1 Finish, 1 Trapdoor age 3-7 years dimensions 22x22x7cm not suitable for children under 36 months