This is the marble roller coaster that can be assembled into 10 different configurations, and it has an attached audio mixer that plays music during a marble's journey around the track. The coaster comes with 10 towers, 12 pieces of track, and five obstacle pieces, including a magnetic hairpin turn, trampoline, and a 360 loop, that can be integrated anywhere into your design. Marbles (five included) are automatically lifted to the topmost tower--18" tall--by a magnetic elevator and released. The coaster includes a digital audio mixer that allows you to plug in your iPod or other MP3 player. The mixer connects to sensors on the coaster; when a marble rolls past one of the sensors, it triggers your iPod to play a song or one of the mixer's 30 pre-programmed sounds (in case you don't own an MP3 player). Mixer requires four C batteries. Ages 6 and up. The manufacturer has confirmed that this item meets U.S. Federal toy safety standards for lead. 40" L x 32" W.