... . 3. High hardness, highly resistant to corrosion and durable. Dorma series stainless steel glass Bi-fold door 1 )1. Material: SUS ... ) We are the manufacture that special in producing sliding door ,swing door,moving gate,folding door ,glass hinge,spider,handle lock ... 24 hours=one year outdoor exposure Certificate New design dorma series stainless steel frameless glass folding doors