10-mm diameter tube insert (Black). The rack fits onto the Biomek 3000, FXp, and NXp Workstations and holds various polystyrene and polypropylene tubes, microfuge tubes and cryovials. To ensure the tube fits properly, inserts must be used. Due to variations among manufacturers, tubes and cryovials should be measured prior to selecting an insert. Measure one inch from the tube bottom and select the insert with the appropriate diameter, or check recommended size inserts from your starter kit. Order is a case of 25 10-mm black insert tubes.