Duration

From FlyFF WIki

Amount of time for which one can use an item. Duration time begins once item is activated/opened. Timer appears in top right hand side of screen in yellow text. One can also see timer by pressing the "J" key, this will bring up the Item Duration screen.

There are two kinds of countdown timers.

In-Game

These type of items will countdown only while you are in game. Examples would be Pink Balloons, Yellow Balloons, Blue Balloons, most Power Ups and Scroll of Amplification ES (S).

Real-Time

These type of items will countdown in real life time. Meaning once you open them they countdown even if your game is off. Examples would be Common Banks, Batteries, Extra Bags and Full Shouts.