This 25mm half-rack Unwire test tube rack is more space-efficient than full-size test tube racks. This half-rack holds sixteen 25mm test tubes or centrifuge tubes in a 4 x 4 array. Fits easily in ice or water baths and won't float. It has all the features of full-size Unwire test tube racks. Molded in blue acetal plastic with Resmer manufacturing technology which makes the rack keep its bright color longer. Useful in a wide temperature range with good chemical resistance. Autoclavable. Color: blue. Material: acetal plastic. Dimensions (L x W x H): 122 x 122 x 75mm. Capacity: 16 tubes. Tube diameter: 25mm. Array: 4 x 4. Nalgene #: 5972-0325.