Complex sentence: Akai is also generally regarded to have built the best 8-track player/recorders that were popular during the 1970s It's best known models were the CR-80 series which are still in use over 35 years later.
Split into simpler sentences: Akai is also generally regarded to have built the best 8-track player/recorders that were popular during the 1970s. Its best known models were the CR-80 series which are still in use over 35 years later.