• Stainless steel brads: for plant tissues • Carbide beads: for microbiological RNA and soil samples • Ceramic: for soft plant, animal and human tissues • Garnet beads: for hard samples, not suited for soil samples • Metal beads: for all types of hard samples • Zirconium oxyde beads: for high viscosity samples • Zirconium silicate beads: for spores and most of tissues • Glass beads: for micro-organisms • Zirconium beads: for hards tissues