Complex sentence: In 1962, the bakelite models were replaced with plastic versions, the first of which was the Model G. This change was driven by Sawyer's new president, Bob Brost, who took over in 1959.
Split into simpler sentences: In 1962, the bakelite models were replaced with plastic versions. The first of these being the Model G. This change was driven by Sawyer's new President, Bob Brost who took over in 1959.