The Tetra washable brush is maufactured from special polyester fibre which has been tapered to a fine piont so only the tips of the fibre needs to contact the latent print.

This is a Tetra R&D Product and is listed as a suitable brush by the PSDB

Unlike fibre glass brushes this product can be washed to restore its original charisteristics and outlast fibre glass brushes 3 to 1.