RPM is the acronym used for revolutions per minute. It measures the number of revolutions completed in one minute around a fixed axis, giving the speed of a mechanical component. It is commonly used to describe the performance of automobile engines.
Like most ballparks built from the 1990s onward, Safeco Field is a 'retro-modern' style ballpark that incorporates many of the features of ballparks built in the 1950s and earlier with modern amenities.
Formerly known as Comiskey Park, U.S. Cellular Field opened April 18, 1991, and was the first new sports facility built in Chicago since Chicago Stadium in 1929. The ballpark features a 53-foot-wide, by 28-foot-tall video screen. The playing field is composed of bluegrass sod, with three different blends of grass.