Megapol AP Grenade
This is the basic grenade. Although it has little explosive power, it remains useful throughout the game as a detonator for larger explosives.
In real time, agents can save themselves from a Brainsucker or Hyperworm attack by dropping a grenade at their feet(or throwing it with 0.0sec detonation). It'll hurt, but it's much better than the alternative. They are more difficult to aim against Poppers due to their suicidal pace and the need to kill them at range. For this situation, the Marsec Proximity Mine may prove more effective and reliable.
To arm, left-click on the grenade and set the time delay. Note, however, that the timer begins as soon as the grenade leaves the agent's hand: on the shortest fuse, the grenade explodes in his face! Also note that the timer cannot be stopped after throwing/dropping, even if an agent picks up the grenade. To detonate the grenade on impact, right-click on it and throw.
"The Megapol AP Grenade is a standard anti-personnel grenade with a timer mechanism. It can also be activated on impact making it highly useful in time-critical combat situations."