Penlight
flashlight with similar form-factor as a pen, to enable easy storage in clothing pockets
A penlight is a small flashlight in the shape of a pen. A penlight usually uses a small light known as an "LED" (Light Emitting Diode) but it can also use a small lightbulb made just for small flashlights.
The LED lights up when power is run through it. Making the penlight light up is as simple as pressing a button, or screwing the end on tighter so it makes contact with the batteries.
Most of the time, penlights use two or three AA, AAA, or AAAA batteries. AAAA are a newer, thinner type of battery, most commonly found in small electronics. It started with the AA size batteries.
Penlights can be made out of plastic or metal, and can be any color. They most often have a little clip, to hold it on your shirt or something.
