A hold-open door mechanism is a great little device that allows you to either keep the door open or have it automatically close after it has been used. The door hold-open device can sometimes need to be adjusted, to alter the closing speed of the mechanism, but this is easily done.
Change Latch Power
In order to properly change your doors latching power, you need to prop open the door using the washer, and then take out the connecting pin. This should be located at the bracket, although you may find it in the closer tube. Take it out, and place it into the closer tube, either at the front, for a glass door, or the back for a more solid wooden door. The rear hole will cause the latch to close, while the front hole reduces pressure and prevents the door from slamming shut.
Adjust the Speed
You may also want to change the speed at which the door closes. At the end of the closer tube, there is a small screw. Turn this using your screwdriver. Clockwise will reduce the closing speed, and counter-clockwise will increase the closing speed. Test out the door before you finish to check the result.