Screw post for binding old books, Photo Album, Create catalogue (Tiles,  Woods, Plastics, Papers, Fabrics,  Acrylic Glass, etc). It's very handy and easy to fix for binding or clamping purpose. It's comes with 2 set. Material: Aluminium, Size : 3/4" or about 2.25cm in length. Only available on this length currently.

You can find more information by typing screw post binding in YouTube or Google for those need more information on that.