LEGO Technic 42020 Twin-Rotor Helicopter Model Kit Features linked spinning rotors, turning front wheel, opening cargo door and a cool rescue-theme design Get familiar with the versatile Technic building elements Taxi along the ground, spin the rotors and take off Rotors are connected with gear wheels and spin together 2-in-1 model: rebuilds into a single-rotor helicopter Twin-rotor Helicopter measures 3" (8cm) high, 8" (22cm) long and 5" (13cm) wide Features linked spinning rotors, turning front wheel, opening cargo door and a cool rescue-theme design. Taxi along the ground, spin the rotors and take off rotors are connected with gear wheels and spin together. 2-in-1 model: rebuilds into a single-rotor helicopter. Twin-rotor helicopter measures 3" (8cm) high, 8" (22cm) long and 5" (13cm) wide.