Promo Mix (sometimes named PromoMix - Only For Dee Jay's) was a vinyl series started in 1979 by AID (Associazione Italiana Disc Jockey, Italian Association of Disc Jockey from Italian language). The subscriber got, every month, a box with some 12" vinyls (6, 7 or 8) with tracks taken from the catalog of major and independent labels like Polygram, Wea, CBS, Sony, CGD, Full Time, Durium, Merak, Ricordi, Energy Production, TIME, Discomagic, Media Records, DWA, Dig It International, Palmares, Disco Più, DJ Movement, Do It Yourself Entertainment, Edinet, Molto, New Music International, Expanded Music, Brioche, only to name a few. Every 12" contains 4 tracks (sometimes 5) taken from the forthcoming releases of every label (and also of their sublabels), and it was a way, for Italian DJs, to have future hits (and even some rare versions) before the official release date. This service was available until June 2005.
AID launched similar concept, but based on CD format, called PC Disc.

Catalog schema of some labels involved:

AID 10XX for Discomagic Records
PRO XXX for Media Records
PRO XXX for X-Energy Records
PMX XXX for TIME (2)
PL PXX for Palmares Records
PRO yearXXX for Disco Più SRL
DWA 00.XX for DWA (Dance World Attack)
DPR XXX for DJ Movement
PROMOMIX XXX/PROMO XXX for WEA
DIG XXX for Dig It International
DJNM XX for New Music International
DO IT PRO XX-XX for Do It Yourself Entertainment
EDN PRO XXX for Edinet Music
PRMLT XXX for Molto
EXS 88XX for Expanded Music