Grenades

Grenades is a category of explosive weapons usable by Rangers. Unlike most weapons, Grenades proper do not ever need to be reloaded (however, Grenade Launchers, also included in this category in-game, do need to be reloaded), but throwing distance is based on both the player's aim and how long the attack button has been held down.

For grenades that detonate based on time, the timer begins immediately upon the attack button being held down, allowing the Ranger to "cook" timed grenades and thus decrease their effective timer (just don't forget to throw the grenade before it detonates in your hand).