many of Line 6's products. In early 2008, Line 6 acquired X2 Digital Wireless, who had introduced digital wireless systems for guitar. Further developing this technology, Line 6 developed and introduced a family of digital wireless microphone systems in 2010. In December 2013, it was confirmed that Line 6 was to be bought by Yamaha Corporation, to operate as a wholly owned subsidiary with the internal management remaining the same. Line 6 products Guitar amplifiers Line 6 produces a number of guitar amplifiers (combos and heads), all featuring amplifier modeling software. In 2004, the Spider II 112 combo amp was released. The Spider III sold over 12,700 units in 2011, the 15-watt Spider IV amp was the best-selling guitar amplifier in America. According to their website, the Spider IV has also been the best-selling 15, 30, 75, and 120 watt amps. The latest model is the Spider V. Pedalboards/stomp boxes Pedal boards range from Pod amp modelers to modeling pedals for delay and other effects, as well as a jam looper. In 2015 Line 6 announced their 'next generation' multi-effects processor/ pedalboard named Helix, similar in function to the Floor Pod and Pod Live series, but with a redesigned interface and body. Portable recording devices The BackTrack and BackTrack+Mic are portable recording devices for electric and acoustic guitars, respectively. Audio interfaces/effects processors The earlier audio interface produced by Line 6, GuitarPort, is replaced by the TonePort line. POD amp modelers are available in a number of versions. Musical instruments Variax is a line of acoustic, bass and electric guitars. Some of the original development team members for the first Variax model introduced in 2002 moved on to other companies, including Damage Control USA and Vox Amplification Ltd. Software Line 6 software includes the Variax Workbench, a software application that can interface a home computer with a Variax electric guitar; the Gearbox, tone editing software; and Pod Farm, which contains all of the modeling features of the POD X3 emulated on the computer. Wireless systems In May 2008, Line 6 announced it had acquired X2 Digital Wireless; it now sells wireless systems for guitar, bass, vocals and wind instruments. Spider V 60 MkII, Spider V 120 MkII, Spider V 240 MkII, and Spider V 240HC MkII all feature built in wireless and are compatible with most Line 6 wireless transmitters. POD product history Guitar Hero World Tour Line 6 products were