Grande Armée

Eagle of a regiment of the Napoleon´s Grande Armée

A "ball-style" finial is commonly mounted to the top of a stationary flagpole. This is sometimes (mistakenly) called a "truck", which is the mechanism that connects the finial to the pole. An urban legend says the ball contains a razor, lighter, and flare. According to the legend, the items were meant to be used to destroy the flag in case the post was overrun by the enemy. A related and less pleasant version says the finial should have a bullet, knife, and matches so the last surviving soldier can continue fighting (with the knife), and if need be destroy the flag with matches (to prevent it from being captured), and take his own life with the bullet.

(wikipedia)