Mantlets are made of interwoven rope and are hung up behind all ironwrok to prevent rivet heads or such like flying into the work if the exterior of the shield is struck by shells. The are able to resist a martini-henry bullet so that it can pass through but with hardly any remaining velocity. They are designed to suit each individual shield and therefore vary in shape. The pieces close to the gun are moveable, being hung from a bar so that they can be pushed close up against the gun at any degree of traning. Mantlets are soaked in chloride of calcium to prevent their being ignited by the blast of the gun.
Replica Mantlets at Landguard Fort
Drawing of the mantlets as fitted in Fort Gilkicker, Gosport, Hampshire (Portsmouth defences)