Lapcon Door Damper Surface Mount Right Hand White Sugatsune LDD-S-R/WT

Instructions are not simple to follow, but adequate. It installed fine and works smoothly and silently. However, after it damps the motion, the door close force is totally inadequate. I put this on a very smoothly-latching and smoothly swinging interior door. But as soon as the door bolt touches its striker plate, that's enough to stop this thing and it won't close the door all the way. I can give it a slight nudge with one finger and it will close, but this thing doesn't have enough force to do it. I cranked the closing force all the way up and still no joy.

Advantages: Compact, unobtrusive, does damp the motion well so there is zero noise as the door closes.
Disadvantages: Final closing force can't pull the door shut. If you have a door with no bolt or latch on it at all, this thing will close it. But any normal door bolt, even a smooth one, will stop it from closing and latching the door.