All steel roller shutters are galvanised by immersing the steel slats in molten zinc which forms a zinc-iron alloy layer. Galvanised steel greatly increases the strength and lifespan of the steel against all weather conditions. Steel roller shutters are comprised of interlocking slats. The ends of every second slat is fitted with a nylon end-lock to prevent the slats from shifting sideways. The T-Bar is fitted with a replaceable ribbed rubber weather seal preventing excess dust, dirt and water from entering under the door. All manually operated doors are fitted with barrel bolt locks.