There is no such thing as a general purpose hair brush. You don't use a brush designed to create volume when you want a smooth finish. So beauty product designers have created a variety of hair brushes to serve a specific purpose. The two categories are bristle type and brush types. Bristle type is perhaps the most important characteristic of a brush, as it often determines which hair type benefits most from the brush. e.g. angle bristles create volume while bristles perpendicular to the barrel produce a flat iron look.
The most common bristle types are: Boar Hair; Nylon; Mixed Boar; Porcupine, Nylon Pin.
Highly recommended for styling, polishing and finishing is the Boar Hair. Because first cut bristles are closest to the scalp of the boar, they help heal the hair and close the cuticle of the hair cortex.
Nylon bristles can be used for straightening and styling. The thickness and quality of the nylon determines what the brush will be used for.
A 100% boar bristle brush is suggested for fine hair. But for thicker hair, Mixed Boar and Nylon brushes is the recommended type.
Contrary to its name the Porcupine does not come from the animal. Instead it is a thick filament of thermic with tufts of boar bristle, mixed-boar bristle or nylon bristle wrapped around it. Difficult hair? Use a porcupine bristle.
Brush Types: Round; flat stylers; vent brushes; paddle/cushion brushes.
The round brush,especially the thermal round brush has long been used for blow drying. Despite all the flat and curling irons it is still the perfect tool to blow dry and style the hair to perfection. Round brushes made of wood with boar bristles, or mixed boar bristles have a little more flexibility than metal brushes.
Flat Stylers feature a flat back and different bristle combinations. Wood flat stylers are popular for updos and extensions. And now that "big hair is back", teasing brushes are once again in demand,
Vent Brushes have openings and vents and are basically used to add volume to any hair type.
Paddle brushes are usually used at detangle or prep hair for coloring. While cushion brushes which conform to the scalp are used for finishing and smoothing.