Scalp Massage Shampoo Brush

Diameter including the non-silicon handle is 7 cm. Not to say that's good or bad, but it surprised me; I was expecting it would be bigger and cover more surface area on my scalp - maybe an 8th or so. To cover just one stripe on the front of my hairline from ear to ear, I need to reposition this 7-8 times; it feels like more of a hassle than I was willing to commit to :) The material feels very good though and it looks very well made overall.