Guitar Hero III Mobile was released for mobile phones in 2007 and 2008, and was developed by MachineWorks Northwest LLC. The base version of the game includes 15 songs from both Guitar Hero II and Guitar Hero III, and has released a three-song add-on pack every month since January 2008. The title has been downloaded by users one million times, with both Verizon and Hands-On Mobile claiming that over 250,000 songs are played a day on the platform.[78] The two companies produced two other mobile-based Guitar Hero games; Guitar Hero III: Backstage Pass, released in July 2008, adds role-playing elements to manage the band's success in addition to the core rhythm game,[79] while the mobile version of Guitar Hero World Tour, released in December 2008, expands each included track for play on both lead guitar and drums, mimicking the expansion of the console series to the full band.[80]