This is a screen technology used in older laptops. Here, the individual pixels are still referred to by row and column addresses, but the amount of electricity flowing through individual pixels cannot be strictly controlled. This results in dull displays—effectively, pixels in a region of the screen can be manipulated, instead of single pixels. Additionally, response times are slower, resulting in dull colours and low contrast. Some passive matrix based screens are HPA (High Performance Addressing), STN (Super Twisted Nematic), and DSTN (Double-layer STN).