With the Rails Kit, you add walls that keep the battle on the track; Drive the fight into the corners, then slingshot into the straightaways; Rails kit includes: 6 curved guard rails and 4 straight guard rails. Drive your dream battle track by adding new curves, intersections, and jumps. Get more supercars for extra strategy and action, or get monstrous supertrucks for a whole new challenge. Anki overdrive requires a starter kit and a compatible mobile device (each sold separately). Set up is easy, simply open the starter kit and build your battle track. The anki overdrive app automatically handles everything else. Na. Na. Size H33.6, W12.7, D1.9cm. For ages 8 years and over. WARNING(S): Not suitable for children under 3 years old. Only for domestic use.