Got this for my 8 year old son for Christmas 2020. I myself had a very cheap rock tumbler as a child in the 80's, and enjoyed it until the cheap plastic barrel broke on that one back then. This NatGeo tumbler seemed of much better construction than the one I had as a child, with a RUBBER barrel instead of plastic, and a thumb-screw that holds the lid on. The rubber barrel is much quieter than the plastic, and the design is good for an easy leak-free seal. Even with quieter operation, we keep this in the basement as it would be quite annoying to have in the living portion of the house. So far, the performance of this tumbler has been very hit or miss. The supplied rocks are of a good quality, but the instructions provided are very rudimentary and you won't get good results with those instructions and the materials provided. The instructions are very nice looking and have nice pictures, but don't really give you the whole story. I know this is an instrument aimed at educating children as to the natural processes that produce smooth stones, but I feel that getting good results helps with that education. As supplied, your stones will not turn out shiny. Smooth, yes, but dull. The instructions tell you to rub them with a bit of mineral oil to get them to shine. Not only does that not work very well, it is also cheating in my opinion. You should be able to get shiny stones with the supplied materials. But, sadly, not with this kit. For good results, I needed to order some tumbler media, namely ceramic cylinders, to help cushion the stones from smashing into each other, and to aid in letting the grit/polish do its job. And then there is the "blinking lights of death" issue. This phenomenon presented itself about three weeks into our first tumble. After a few minutes of operation, the motor would shut itself off and all the red lights would flash rapidly. Unplug the unit for a minute or so, and it would resume operation, sometimes. At first I thought we had overloaded it, but being as how we had lost a lot of mass from the stones in the first few weeks, I knew this was not the case. Could it be temperature? It is kind of cool in the basement (50degF). But, no, it wasn't that either. Finally, it got to the point that the unit wouldn't turn on at all, just go into red blinky mode whenever the power was turned on. Outside the return window, I had only one option. Take the sucker apart and see if I could spot the problem. What ended up being the issue was the motor getting filled up with a very fine black powder. Not entirely sure what the powder is, but blowing it out of the motor with an air compressor got us back up and running. You could use the canned air they sell for computers if you don't have an air compressor. If you need to perform this, there are 4 screws on the bottom, hidden under the 4 corner rubber feet. Just peel the feet off and put them somewhere clean until you are done and they'll stick right back on after you return the screws. If you aren't handy at all, I'd stay away from this model. I don't see how anyone gets more than a month or two of performance out of it without having issues. The issue, for us, presented itself before we got even one batch of rocks tumbled. This could have been a real disappointment for my son and I had I not found a solution. THE GOOD: Rubber barrel for quiet(er) operation The barrel is easy to use and leak free Relatively inexpensive (get what you pay for) Has options to set # of days up to 7 Seems to be efficient when it is running THE BAD: Will require strange maintenance to keep running Instructions and supplies inadequate for good results Tumble speed is rather fast, and is not adjustable. Only enough rocks and grits for one tumble Good Luck fellow Amazonians!