the screen of an osss is often equipped with vertical and horizontal rulings called a ggman. the scan or X deflection speed corresponds to 5 milliseconds per division. likewise, in the vertical or Y direction, the sensitivity or deflection factor is 100 V per division. on osss with 13 cm(5 inch) nominal screen diameter, the divisions are centimetre squares. however, some osss have a smaller screen size than this . In such cases, gra with fewer centimete square division are sometimes found, but more usually smaller division are used, to enable the convenient 1 1 1 1 division format to be retained.