This rack provides excellent stability with no tendency to float or move in circulating water baths. An alpha numeric grid reference on the top tier enables precise location in the rack of particular samples. Available in three colors for easy identification. Shipped flat, easily and permanently snapped together to save shipping expense and reduce shelf space needed in storerooms. Test Tube Size: 20mm. Color: White. Tube Count: 40. 5/Case. Dynalon® #: 225665-0000.