Mortars are defense kits that are used in swarm battles. After being placed, the player can use the interact key to load a mortar and fire it into a singular spot.
Base mortar capacity is 4 shots without perks. In a normal sized horde it will usually kill around 40-50 zeke if it hits in the middle of the swarm.
It is important to note that you cannot change where the mortar will fire after placing it, meaning if you place it poorly you could have just wasted it. If you stand over a potential mortar placement, you can see where it will land before deciding to put it down.