Full-size Unwire test tube racks securely hold a full load of test tubes or centrifuge tubes in the following popular sizes: 13-, 16-, 20-, 25- and 30-mm. Up to 72 of the smaller diameter tubes can be held at once. Molded in six bright, permanent colors Resmer? manufacturing technology makes these racks keep their bright colors longer. Useful in a wide temperature range with good chemical resistance.