Designed for use with a drill for rotation that stimulates hair growth, the longer rows of 3/4" bristles pull up hair and alternate with shorter rows of 3/8" bristles that fluff and pop the hair. In addition, the rotation from the brush against the coat provides a great way to train the hair. Brush head is 5-3/8" long. Drill not included. | Weaver Livestock Drill Rotation Brush in Purple | Size 5-3/8"