11-mm Diameter Insert, White, for 1.5 mL Microfuge Tubes. The rack fits onto Biomek 3000, FXp and NXp workstations and holds various-sized polystyrene and polypropylene tubes, Microfuge Tubes and cryovials. To ensure proper tube fit, 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 for size using inserts from your starter kit. Order is a case of 25 11-mm diameter 1.5 mL microfuge white insert tubes.