Explosive are used in Zombie HQ to clear out zombie hordes or to keep them at bay while escorting Survivors or fighting a beast.
Machine Gun Sentry: High Caliber Automated Sentry with a fast rate or fire but does less Damage then Rocket Sentries.
Rocket Sentry: Expensive and slow but inflicts large amounts of damage against infected and anything it hits including the player.
MineField: Places down a set of Area-Denial explosives that explode only when detecting infected, Inflicts heavy amounts of damage and causes no friendly fire against the player nor survivors.
Hand Grenade: Timed explosive that explodes automatically when hitting a zombie inflicting a decent amount of damage along with a cheap restocking price.