Other notable bootlegs to appear in the early 1970s were "Yellow Matter Custard", containing 14 BBC Radio performances from 1963, (originally these tracks were thought to be from the Decca audition of January 1962, and Lennon himself told McCartney about the album) and "Sweet Apple Trax", a two-volume four-disc collection of songs and jams from the "Get Back" rehearsal sessions first issued in 1974. In 1977, a copy of the Beatles' Decca audition tape was bought by a collector, who released the songs over a series of seven 45 rpm singles pressed on coloured vinyl with full colour picture sleeves. Bootleggers of this era often copied and repackaged each other's releases, so popular titles often appeared from more than one bootleg label. The biggest labels for Beatles material in the 1970s were Kornyfone (TAKRL), ContraBand, Trademark of Quality and Wizardo.