First of all, we have a new brand to introduce to the site called Bommer. We will be adding more new items from this brand to our site in the near future. Right now we have only a few items added, and the items are called Spring Pivot Hinges. One is heavy duty and the other is more of a medium duty spring pivot hinge.  width= So basically how this spring pivot hinge works is that you would mount the set to the top and bottom of your door and it works like a double acting hinge, meaning that this hinge can pivot in both directions, or in other words the door can swing both in and out. A few examples where you may most likely find these type of doors are in department stores, the doors in the back of the store where they keep storage and restaurants, the doors leading to the kitchen areas, so the people working there don't have to set things down to open the door - it makes it easy for them to bring out a big plate of food hands free. My grandma also had the swinging doors, saloon style leading in to her kitchen before they remodeled. I am sure you can think up several other places these style doors are found, and they are more common than one might think. The Bommer Spring Pivot Hinges are made with anti friction bearings, have a steel mechanism, the spring tension can be adjusted to fit your specific needs, and these also have a hold open capability when opened about 85 degrees. You don't have to worry about getting the handing when ordering, because these are non handed hinges, making it one less thing to have to figure out when placing your order. The difference mainly between the medium duty and the heavy duty is the maximum door weight limit. The medium hinges can only hold up to 90 lbs, which may be all you need - where as the heavy duty hinge can hold up to 150 lbs.