Soft 

The true purpose of the soft brush is to lay the hairs on top of your hair into your pattern after your hard and medium brush sessions. Brushing with a soft brush also helps distribute product evenly through your hair, which provides added shine and volume to your waves.

Medium

Medium brushes also puts less stress on the hair and scalp than hard brushes, allowing you room to brush for longer periods if you like without damaging your hair or wave pattern.

Hard

Some wavers use their hard brush as a shower brush as well so it can help in two areas that your other brushes can't. Hard brushes also help stimulate the scalp to promote healthier hair growth. When you get a low fresh cut, this brush might have to sit on the shelf for a few weeks.