Mould King 11013 Double Helix Roller Coaster Building Set - 2,174 Piece STEM Educational Toy for Kids & Adults | Creative Construction Model Kit for Birthday Gifts & Home Decoration | Fun DIY Project for Family Bonding & Engineering Enthusiasts

This Double Helix Coaster is equipped with two helix/spiral rails. One is a helix lift using a worm gear gearbox operated by hand crank or a motor to push many carts to the top continuously, another one is a helix slide rail for carts to coast down in a spiral. Both of them were built in the same tower just like the shape of DNA! 
 
The helix lift is safer, more reliable, and compact. The whole thing was built on two base plates only.

Key Features:

• Over 2100pcs
• Two Helix/Spiral Rails
• Elevator Mechanism
• Motorised Climbing
• DNA Shape
• Two base plates
• Detailed Surroundings & Buildings
• 55cm high
• Building Instruction Booklet Included