Marble Genius Physics Fun – Run Accessory Add-On Set 5 pcs

2 – Y splitters alternate moving the marbles in two different directions (this is one of our most requested pieces). Standard toy size marbles (5/8 inch or smaller) work with this set (no marbles included with this set). Manufactured by Marble Genius. 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. 5 of our most popular see-through marble run pieces allow you to see all the action.