The conical shaped wells of the Bio-PlasŪ brand microcentrifuge tube racks keep tubes centered and upright. Available in multiple colors for ease in separating and identifying batches. Precise spacing of the wells to provides excellent uniformity. Manufactured of polypropylene, these racks are suitable for autoclaving. (15 minutes, 15 lbs @ 120°C). One side of the rack is designed to accommodate 0.5mL Microcentrifuge tubes. The reverse side holds 1.5mL to 2.0mL snap-cap microcentrifuge tubes as well as screw-cap tubes. The clear polypropylene cover easily snaps on to keep it firmly in place during transportation and storage. A recessed area in the top of the covers allows for secure stacking of racks, on top of another. The snap-on cover is designed to accommodate the extra height of screw-cap Microcentrifuge tubes. Racks are available in 64 or 96-Well configuration. Order rack covers separately which follow the listing of available racks.