Chicago's classic "25 or 6 to 4"  arranged for 5 piece horn section including trumpet, alto sax, tenor sax, trombone and baritone sax plus rhythm lead sheet.  This is an Instrumental feature meaing the horns play both the traditional horn parts and the vocal parts.  You can perform as a vocal by having the horns NOT play the vocal lines.  Great Fun and in the original key. Note this includes a horn parts, a horn score and original lead sheet for rhythm.  No Vocals.  Not that the YouTube version does not the have lead or vocal.  This chart does have the horns playing the lead part.