It is used to provide lifting position for handling by crane. Usually two bracket are provide per shutter.
They are secured at the top of the soldier using four M16 x 35mm bolts and nuts.
In Mark I the bracket consist of a bend plate and a ‘U’ shaped Ø16mm rod.
In Mark II the bracket consist of a ‘U’ shaped Ø16mm rod welded to 10mm thick base plate.