"無限 (Unlimited)" is F.I.R.'s 2nd album. It was released on April 8, 2005. This album also has Thorn Bird Glory Limited Edition. "無限 (Unlimited)" stayed in G-music chart for 21 weeks (3rd place in 2005).
Part of songs in this album was produced in Sarm West Studio in London. The songs "千年之戀", "LOVE*3", "應許之地", "把愛放開", "刺鳥", "死心的理由" and the instrumental tracks "盛宴..." and "傳說..." were coordinated with London Philharmonic Orchestra.
The track "千年之戀" (Thousand Years of Love) was nominated for Top 10 Gold Songs at the Hong Kong TVB8 Awards, presented by television station TVB8, in 2005.
The album was awarded one of the Top 10 Selling Mandarin Albums of the Year at the 2005 IFPI Hong Kong Album Sales Awards, presented by the Hong Kong branch of IFPI.
The 13th track "What's Next?", just like last album, vaguely announced the song of the next album. The lyrics announced that their third album would be produced in New York, and the song should have the genre, Jazz rock.