Draw in high resolution on your TV screen.
"This highly succesful Light Pen fits neatly onto the rear of the computer. The operating software now runs faster and supports 16 pre-defined instructions. You can change all the colours (border, paper, ink), draw circles, arcs, boxes, lines and insert text onto the screen. There are also features to draw freehand and animate on the 48K Spectrum, you can retain and animate 5 screens. You can also use the machine code on its own in your own programs."