What is a pager, and why are Hezbollah militants still using such outdated device?

A pager, or beeper, is a small, battery-operated device that alerts you with a sound or vibration when it gets a signal. It can display a numeric message or, in the case of alphanumeric pagers, a text message. Pagers were widely used from the late 1980s through the 1990s. By the 2000s, however, smaller, more affordable cell phones with longer battery life caused many people to transition to cellular communication. However, the tiny device, which is widely used by the Hezbollah group in Lebanon killed several people and injured more than 2,800 people.