Nonadjustable Conceal Hinge (SOSS Type) Material:zamak body and stainless steel Finishes:satin stainless steel / polish stainless steel / satin nickle / satin chrome / polish chrome / antique brass / antique copper / gold surface / etc Function: can be used not only in wood like wood door and floor screen,but also in metal,including steel entry doors,metal cabinet doors,machine tools and transportation vehicles. they are mainly used in custom cabinetry applications in restaurants,homes and offices and bi-fold applications for creating a clean look,and they are totally invisible from either side when the door is closed.