According to McCarty, Beck developed the riff after borrowing Page's prototype fuzz box, designed for him by Roger Mayer. When he played the lick for the band, they felt that it was a perfect fit: "this great sounding riff emerged... I mean Beck just nailed it", rhythm guitarist Chris Dreja recalled. The group returned to Advision on 20 April to complete the song. Beck was able to achieve the sitar-like hook by bending the higher notes on his guitar using his own Tone Bender unit to get the distinctive tone. Music writer Alan diPerna describes it as "microtonal string bending", while Relf biographer David French calls Beck's sound a "violin-like fuzz". While simultaneously sounding the open D string, he also added a droning quality reminiscent of the sitar's sympathetic strings.