One downfall of this design is that it can only be used with solid-core, inherently sturdy doors. Since this product only braces the bottom part of the door, instead of the middle doorknob section like the alternatives, a hollow-cardboard-core door (e.g., interior doors) will simply break at the bottom where the DoorJammer braces it. The alternatives that brace against the doorknob section are much better (although not perfect) for hollow-cardboard-core doors, as they reinforce a section of the door that is already made stronger by the doorknob being latched and/or locked into the doorframe.