In a CRT display, the refresh rate is the number of times per second that the electron beam scans through the screen. Since the beam travels row-wise from the top to the bottom, CRT displays have two refresh rates associated. The Horizontal Refresh Rate is the number of rows scanned by the beam per second. This is usually in the order of Kilohertz and is of not much importance. The Vertical Refresh Rate is the number of times all the rows in the screen are refreshed, and this is in the range of 50 to 150 Hertz. Normal references to “refresh rate” are to the Vertical Refresh Rate.