Grandfather's Mole

My grandfather has recently started a course called "Computers for the Terrified." He's nearly eighty and, although he used to be an engineer within the British Royal Air Force, is completely stuck when it comes to computers. He came back from his first evening at this course. When asked how it had gone, he replied, "Yes, it was really good. I really enjoyed it, but I really couldn't get to grips with my mole." I stopped for a second, completely puzzled, until I realized he was talking about the mouse.