One of the great things about owning a canon is that you have the ability to use nikon lenses on them in manual mode. To accomplish this, you need an adapter. You can get a dumb adapter which forces you to use the clicked aperture. Then there's the adapters which have a slide/lever to control the aperture lever built into the back of every nikon lens. These adapters where originally quite expensive, but as with many accessories, it's only a matter of time till china does its thing. Thankfully in this case they did a decent enough job.
Having the aperture control adapter does two big things for you: it gives you a clickless aperture adjustment, and more importantly it allows you to use the newer nikon G lenses which were built without an aperture ring.
How is it built? All metal thankfully, with reasonably tight tolerances. it fits onto my lenses quite snugly, which is good. To get the adapter off is a bit tricky at first, but once you get the hang of pressing the lever and twisting the adapter with the same hand, it's a snap. The fit onto the camera body is not as snug. Not loose, but i wish it were tighter. I wouldn't recommend it with very large lenses without lens support. you can visibly see the separation flex if you press down on the lens. Thankfully, pressing down on the lens is not something a mentally stable person does when shooting, so don't worry about it.
The aperture adjustment ring is nice and smooth, grease is visible on the inner workings, but does not appear to be in excess, good. The one thing i would keep an eye on are the screws, make sure they're snug, especially the one attached to the release lever.