Self closing door hinges are nothing more than a spring hinge. Spring hinges have tension springs inside the barrel that causes the door to close after releasing the door. Some cities require the use of self closing hinges for fire safety, but this is not required everywhere. Usually you would use at least two spring hinges per door. So if your door has 3 hinges, you would put a spring hinge top and bottom and a regular hinge in between. However, you may consider putting a spring hinge in each location. Most spring hinges are slightly adjustable by removing a pin, then tightening the spring with an Allen wrench - then re-inserting the pin while the spring is tight. Self Closing door hinges are handy in cold or warm climate areas as they close behind you keeping your warm/cold air inside your home. Spring hinges come in various sizes. Probably the most common is a 4" hinge with 5/8" rounded corners. Click on the image below for more information or to purchase. Emtek 4 Spring Door Hinge