Mk 2 Grenade

The Hand Grenade is a standard infantry weapon and is fairly common in Half-Life. Most HECU Marines carry a few of these and use them to flush out and/or destroy enemies. This grenade is unmistakably modeled after the MK II defensive fragmentation grenade. The player finds his first hand grenades in the game's third chapter, Unforeseen Consequences, in a secure storage room which can only be accessed with the help of a scientist. Since this is an optional supply cache, it can easily be missed. If so, the player will instead find their first grenade in the next chapter, Office Complex.

Usage
These grenades are very low bounce and, once they land, do not roll at all. While they will bounce off of walls and ceilings, they tend to stop right where they land on the ground, so it's fairly easy to land one right next to a stationary enemy. Grenades can also be 'cooked' (that is, armed and then held for a moment before throwing to minimize the time the target has to avoid the blast) by pressing and holding the primary fire button. The grenade's major downside is that it has no visible nor audible timer, so that it is hard for players to see whether or not a grenade has already been launched, ending in players basically blowing themselves up.

Trivia

 * The Frag Grenade in Team Fortress Classic uses the Grenade's ground model.
 * In Half-Life: Day One, the player can hold up to 15 frag grenades. This explains why there are 15 Frag Grenades in certain areas, such as the weapons stash in Unforeseen Consequences.