Digitizer tablets or graphics tablets are pressure-sensitive data input devices that allow users to select and draw images with a special pen called a stylus or a mouse-like device called a puck. Pucks feature a series of buttons and a lens with crosshairs that allows users to select images with greater accuracy. Both pens and pucks can be wireless devices or attached to digitizer tablets via cords or wires. Typically, pucks are used to trace highly detailed engineering drawings or medical X-rays while pens are used for a variety of sketching and tracing applications. With digitizer tablets, producing an image creates a series of X,Y coordinates as either a continuous stream or a series of end points. Pens that record vector graphics in three-dimensional space are also available. The drawings that users produce with digitizer tables are stored as mathematical line segments. Outputs can be sent to computer aided design (CAD) applications, graphics programs, or related software applications.