What is the best kind of knife to use as self-defense?

Knives are used for various purposes including self-defense. Tactical pens are very important self-defense weapons. The tactical pen is an easily portable weapon for bags and pockets. If someone falls into danger and has this pen with him other than any other tool. A person can use this for his protection. This is the main important fact about tactical pens. It is really interesting to see how a harmless pen can convert into the most lethal weapon for self-defense. These pens look like ordinary writing pens. You can get these tactical pens to increase your defense measures.