Spirals, curves, straightaways, accelerators, and a seesaw combine to make Quadrilla's Xcellerator the pinnacle of speedy marble run construction sets. Quadrilla's Xcellerator will make any mopey marble put the pedal to the medal with it's velocity-increasing design. Quadrilla's Xcellerator can be combined seamlessly with Quadrilla's other marble run sets. All Quadrilla marble run sets are crafted with high quality birch and rubber wood for long-lasting marble racing fun! For ages four years and up.