The weathered brass finish is a hand applied chemical application that speeds up the weathering process. We used to do all that finishing here in house but then the EPA came-a-knockin. Apparently the regulations on using the chemicals you need to do this were tremendous. So we decided to just have the application done overseas along with the molds. That process is done in the same factory we have our molds and stamped copper products made. We do however have a solution based off of the same chemicals that allows us to weather brass just about anything. Its a mixture of a few different acids that will change just about any metal except for Stainless Steel to a rich brown "weathered brass/bronze" look. We use this for our one off custom brackets and for a few other things such as nuts and bolts. As far as how long the finish lasts. It lasts a long time! Now it is a hand applied finish so some will weaher slightly different then others, it really comes down to environment. But at some point it will too go green/patina and change just like a raw brass. Advantage is you dont have to start with a bright shiney brass fixture. Hope this helps. Joey D.