Product review (2 stars): The brush is huge; much larger than 1. ...
The brush is huge; much larger than 1.5 and 2 inches. Your hair must be at least shoulder length or longer.
The barrels are 1.5 and 2 inches, but when the long bristles of the brush are added they measure 3 and 4 inches.
(I can't comment on the products' function.))