When high demands are asked for, an optimal density of the filling such as heavy and hard brush fibers which are speed resistant, the double banded spiral brush is without a doubt the best choice.
The construction of the double banded spiral brush exists out of two metal bands of which the outer band clasps the inner band.
This construction has the advantage that the density of the filling can be measured very well and all types of brush filling can be used from very delicate to very heavy steel wires or synthetic fibers. The retention of the hairs is also guaranteed. Another advantage is that if damage happens to occur to a hair bundle with the double banded system, the damage stays locally, while other hair bundles stay intact.