Large, specialized recovery units are welded, painted and then secured to a pre-built truck. The resulting rig is strong enough to tow buses and other large vehicles. | http://www.sciencechannel.com/tv-shows/how-its-made/ Watch full episodes: http://bit.ly/HowItsMadeFullEpisodes Subscribe to Science Channel: http://www.youtube.com/subscription_center?add_user=sciencechannel Check out SCI2 for infinitely awesome science videos. Every day. http://bit.ly/SCI2YT Download the TestTube app: http://testu.be/1ndmmMq