Increase the fun as well as the strength and stability of your marble run by leveraging our Round n Round topper pieces.
6 Round n Round pieces including 2 Round n Round s increase the fun and overall playability of your existing marble run toy.
4 Round n Round Topper pieces allow you to increase the stability and complexity of the marble runs you build.
Standard toy size marbles (5/8 inch or smaller) work with this set (no marbles included with this set).
Compatible with Marbulous Marble Run Toys including our Marble Genius Marble Run Starter Set (60 pc.), Super Set (85 pc.), Extreme Set (125 pc.), & 8 Accessory Sets.
