The 96-well rack holds tube in an 8x12 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 alphanumerically labeled and are available in 12 colors including 5 fluorescent colors. Both racks and lids are designed to be stackable and are autoclavable. Lids are sold separately. Made of polypropylene. Dimensions: 9" length x 4½" width x 1" thickness (excluding lid).