Dre is renowned for constantly evolving his production style through the years, while always keeping in touch with his roots and re-shaping elements from previous work. In the start of his career as a producer for the World Class Wreckin Cru with DJ Alonzo Williams in the mid-1980s, his beats were in the electro-hop style pioneered by The Unknown DJ, and that of early hip-hop groups like the Beastie Boys and Whodini. These influences are evident in Eazy-E's 1986 song "Boyz-n-the-Hood", which Dre produced. Sampling was at the time a key element of Dre's production, the E-mu SP-1200 being his primary instrument in the N.W.A days.