It is made of plain steel ,can be used in the door of ship ,car and the tool box. This box hinge is made of plain steel ,both sides of it can be flat.It can be used to the door of ship,car ,and security door.It also can be used to the tool box.We have all kinds of this series products from 40# to 260#.If any kinds of products be of interest to you ,please tell us ,we wil give you a lowest ...