The 96-well rack holds tubes in an 8 x 12 format. One side of the reversible rack holds 96 1.5 ml, 1.8 ml or 2.0 ml microcentrifuge tubes. The other side holds 96 0.5 ml tubes. Racks are alpha-numerically labeled and are available in 12 colors including 5 fluorescent colors. Both racks are designed to be stackable and are autoclavable.