Complex sentence: The improved flash was introduced in 1970 as the Vivitar 283 and quickly became the number one professional and enthusiasts flash unit, outselling all its competitors combined and selling 3,000,000 by 1973.
Split into simpler sentences: The improved flash was introduced in 1970 as the Vivitar 283. The Vivitar 283 quickly became the number one professional and enthusiasts flash unit, outselling all its competitors combined and selling 3,000,000 by 1973.