It must be a brush with firm bristles (not flexible) with single height (not bi-tufted) and featuring excellent grip to the roots and tips. Condor recommends the Shana (6826)
The brush must feature soft combing, just enough for settling the frizzed hair and finishing. Condor recommends the 9630
Ideally, the dryer should be 3 cm apart from the hair and the brush. Another factor that helps preserving the brush and its bristles is to avoid pressing the dryer against the brush, in other words, not "beating" the brush with the dryer during the hairstyling process.