Edit Review June 2020 (one year of use): One year later update: I am having to replace the eraser almost one year later. I have been messing with it to keep it going for the last month & thought this is silly, it only cost around ten dollars get another one! I found that over te course of the year it lost power regardless of whether the batteries were new or not. It also slowed down when in use, so it rotated great until I put it on the paper! I am looking at this now as something which has a limited life span before it needs replacement. Given that it has been a year, I think one dollar a month is still a great deal so I am not changing the rating. Maybe the motor on the 60 dollar one would last four years, but I would still be ahead with this one because the cost is so low. I am going to try a different manufacturer with an identical design to see if there is any difference but I expect it is the same eraser with a different name printed on the barrel. One thing is for sure, I do not need replacement erasers, my bag is still almost full. I use this daily so that speaks well to how generous they were in providing replacements. The only other thing new after a year of use is I found that with a sanding stick I could turn the point into a micro size on the end, or with the thicker one just a pointed shape and both have improved the results I get from the eraser. It is well worth trying this out and I think there is a YouTube vid out there somewhere (art gear gude maybe) who shows you how to do it if my explanation is not clear. Otherwise the initial review below remains unchanged. Review from June 2019: I have two electric erasers and this one is the better of the two. The other one is a squat wider design and it is a real pain to change the batteries in it and it doesn't work nearly as well. (In other words the second one is a complete piece of junk.) That being said after trying other ones this one is 5 star in comparing features, ease of use, build quality and how long the battery will run the eraser before it needs to be replaced. While I initially found it awkward to hold the slide down while erasing, I found that with use it became quite easy and now have no problem. The build quality is nice and solid. There isn't a lot that can go wrong as it is not overly complicated in the build. There are two different sizes of erasers and ends supplied. A thicker one which is great for erasing a field of marks and a fine one useful where you want to erase a few lines without erasing what is around the area to be erased. I found myself changing back and forth so often that I just purchased a second eraser in the other color choice. So now I have a black one loaded with the thicker eraser and a white one loaded with the thinner eraser. As these are inexpensive, I had no qualms in being lazy! You are provided with several replacement ends and a bunch of erasers. I suspect it will be years before I need more. The end holding the thicker eraser is made of metal, the thinner one made of plastic.. I actually think the plastic one is a bit more rigid. Make sure you extend the eraser before it is even with the holder end. If you fail to do that the edges, particularly of the metal one, will bite into the paper causing damage. If the eraser falls back into the holder it can be difficult to grab hold of without excessively bending the holder end. I use an exacto knife to grab the eraser from the side, move it up to the desired amount, squeeze the holder so it will not fall back or move forward more than desired and then reinsert it into the eraser. Again with practice it will be a breeze. Don't extend the eraser too far or it will jiggle all around while in use and will break quite easily. Again practice will soon make it easy to determine how far you personally feel works best for you. The second eraser I purchased had to be replaced as when you touched the paper it stopped rotating, but the seller quickly sent a replacement so no big deal. You will find that as your battery runs out you get less and less rotation when in use. In terms of how long the battery last, that is of course dependent on how often you need to erase! This one seems to take less power than the other manufacturer's I tired, but the difference is minimal. With the fine point eraser you can use it to achieve some unique effects. If you are for example working on an eye,, you can using only the edge of the eraser, erase a tiny speck in many spots to give the eye a more realistic look. Or in other words it helps you to make striations in the eye which look more realistic. They also provided a brush and I highly recommend brushing where you erase to remove the pigment dust. As I have two of these and two brushes I dedicated one to brushing off crud and the second one to use with a tiny bit of solvent and "sweep" across a big expanse of background color to get some interesting effects. When dry I also use that one with pastels which are chalky and really...