4 Plugs is the seventh album by The Mad Capsule Markets. The album has been known as one of the band's more aggressive and heavier albums, as it was a departure from the original melodic Japanese rock and punk sound to a more metal and rap-based style, and the debut of Takeshi's experimentation of playing bass guitar with effects and downtuning. Most fans welcomed this newer sound and style, and the band attracted a new fanbase, but some fans of the original more experimental sound felt let down by the newer nu metal sound.
Due to creative differences on this album founding support guitarist Ishigaki didn't have much input (except where his guitar is similar to the band's older material on "Normal Life"), which later led to his departure from the band.
This album also featured almost fully English songs such as "Walk!" and "Don't Suss Me Out".