Complex sentence: The most common form of the vinyl single is the 45 or 7-inch, the names are derived from its play speed, 45 rpm, and the standard diameter, 7 inches (18 cm).
Split into simpler sentences: The most common form of the vinyl single is the 45 or 7-inch. The names are derived from its play speed, 45 rpm, and the standard diameter, 7 inches (18 cm).