Nikon Lens PenI've bought several from here.
This little pen-shaped tool offers two ways to clean your camera and lenses in one convenient and affordable package.
This is not marketed or intended for use in cleaning your camera's sensor. It is not a "forever" thing and will wear out with use requiring that you buy more.
Some people think that because this is a pen it might contain cleaning liquid - it does not. It is just a brush on one end and a soft rubbery tip on the other and uses dry cleaning only. Read on for more details about the dry substance. Unless you breath a little on the glass surface first to introduce a little moisture.
For me, it is a nice camera-bag item. It is not the only cleaning device I use, but I like having a few around. I keep one in my desk and one in each camera bag. As the rubber tip wears out, I still hang onto them for the brush end, but I break off the rubber tip so I don't get confused.
The brush works great for removing large dirt particles and then slides inside of the pen itself for easy and safe storage.
The real cleaning happens at the other end where a felt or other soft-cloth-like thing is affixed to a rubberized tip with a concave design. This design allows the tip to change to the radius of your lens.
The way that I use this end is that I start in the center of the lens and make circles of increasing radius to the outer edge and I use a light touch while doing this. This removes finger prints or other spots.
Often, even if this first pass appeared to do the job, I'll "haaaah" a little mist from my breath onto the glass and then use the ever-increasing circles to clean it again. This moisture leaves a visible path so you're sure that you don't miss a spot. It also helps loosen spots that may have dried.
The biggest complaint of mine is that there are no instructions on cleaning either end of the brush as they get used and themselves become dirty.
There are lots of other good soft cloths and micro fibers out there. Those have the advantage of being washable or otherwise cleanable.
But, I don't find that a folded up micro fiber cloth is a good thing floating around picking up seeds and other dirt which just seem to seek them out when I open up my camera bag.