4 Pack Flush Bolts, 10cm x 1.8cm (Width) Made of stainless steel, brushed finish, reliable and durable. Designed for French double doors The flush bolt can be installed downward or upward This flush bolt is usually installed on the top and bottom leading edge of the slave door in French doors and double door installations. They can also be installed in the leading edge of the door on single doors for added security. Comes with a complete set of installation screws (no instructions included, carpenter installation will be best)