There are three common types of tire gauges. Pencil gauges are shaped like a pen or pencil and, when pressed on your tire's valve, display the pressure on a white column pushed out of the rear of the gauge by the tire's pressure. They are handy to store and mostly readable in good light if you have decent eyesight. Dial gauges, also called analog, have a clock-like display face that shows the pressure level and are much easier to read—as long as you can hold them where you can see the face. Digital tire gauges, the most advanced type, display pressure on an LCD screen. They are generally the most accurate and are easy to read because the pressure remains on the screen after you remove it from the valve. Dial and digital gauges are easiest to use, but pencil gauges are more compact and easier to store.