The doors I use this wedge on have wide and narrow gaps at the bottom and are spring loaded to close. I thought that the larger size would be able to handle them all. What I found was that in a lot of cases the door would still creep closed. This was on smooth surfaced floors. Often times I would try to force it farther up the wedge but the rubber ribs prevented any further positioning, so the wedge didn't have the downward force necessary to hold the door.