One of the most important pieces for your drapery hardware treatment are brackets and supports. Brackets for curtain rods are typically measured by their return size. The return size is the distance from the center of the brackets cradle to the wall. Or, the exact distance from where your curtain will hang when installed from the wall. For example a 4 1/2" Return Bracket will project your drapery about 4 1/2" from the wall. The actual size of the bracket will be an inch or so larger.
Two other sizes you'll encounter when selecting brackets are the clearance and projection measurements. Projection is the easiest size to understand, it just tells you exactly how long the bracket is from the tip of its nose to the back. The clearance measurement represents how much room you may have beneath the bracket to install a second layer of fabric without interfering with the front layer. Most of the time, the only size you'll need to consider is the return. You'll want a larger return for your bracket if you need to clear an obstacle in your window like outside mount wood blinds or shutters, or perhaps, the handle of a sliding glass door.
Curtain rod brackets are available in several configurations. Single and double brackets are common with most collections. Double brackets allow you to create a layered treatment. Ceiling mount brackets are a nice option if you have limited wall space. Specialty brackets like bypass are also available. When used with coordinating bypass rings, these brackets will allow you to open and close your drapery across the supports.