We just finished installing 6 sets of engineering integrated stairs for an Australia customer. There are 3 sets of U shape staircases and 3 sets of spiral staircases.
In this order, we all use International standard 304 stainless steel material, even a small screw accessory is made by solid stainless steel. Before shipping, we processed trial assembling precisely to make sure everything was correct. After finished trial assembling , we packed each unit (including all accessories) in a plywood separately, so that customer can install easy in future.