Mantlets offer similar protection for your troops against enemy ranged units that Cats do, although Cats are slightly better and can take more damage.
They are available to all factions wihtin the game. Mantlets contain an arrow slit, which will allow friendly nearby Archers or other ranged units to fire at enemy troops, although enemy troops will not be able to fire at your own troops and instead, the Mantlet wil take the damage.
Enemy units must destroy the Mantlet before they can actually attack your nearby troops, and the more Mantlets you have around your troops, the harder this task is because your troops are more protected from additional angles.
Due to the fact that Mantlets are so small, this may be necessary in order to fully protect your Army. Mantlets can absorb a large amount of damage off ranged units, although melee units can quickly destroy them. Fire, for example from burning carts, can also cause a lot of damage to them, as well as man traps or other similar defence systems.
Note that the Ice Queen can still freeze units that are stationed behind Mantlets. Dragons can still attack units stationed behind Mantlets as well, as can Giant Demonic Bats, although any damage performed by White Witches will damage the Mantlet first before they can attack the units behind them. You will need 10 gold for a Mantlet, along with 1 peasant from the campfire before it can be recruited.
Tip: Rushing into a battle using Mantlets can greatly help to increase the durability of your own units and help to defeat enemy units much quicker. Enemy ranged units will almost always hit the Mantlets rather than your troops, so it ensures that your troops survive much longer.