The rubber bands that adjust the brush length allow for many sounds. I use one adjusted to the "solid" setting- to get a nice heavy beat, and the other one loose. I also use one of these at solid setting with another more conventional nylon brush for even more variety. I can see the little rubber bands that adjust length breaking at some point, but probably could use any small rubber band to achieve the same thing.
Bottom Line Yes, I would recommend this to a friend
Nice alternative to metal brushes, different sound. These have a nice weight, and give a nice mellow brush sound on the cajon. Seems to be fairly well made. Don't know yet how it will hold up to heavy use. A little pricey for what they are.