You can even get both in one brush. important criteria for your choice includes handling and the hardness of the bristles. if you regularly want to include your entire back in the massage then your brush should have a handle - ideally with a firm grip - so the head of the brush cannot fall off even when massaging your back vigorously. the best way to test the hardness of your massage brush is on the inside of your forearm. if it feels nice then those are the right bristles for you!