Test tubes hang in there in any position, even inverted. Grip Racks will assist you in decanting and in water bath work. Four retainer fingers in the two plates of the rack hold tubes firmly in any position with no fear of their dislodging while decanting. The racks are molded of a special blend of autoclavable polypropylene that is heavier than water for submerging in water baths. Each rack features end plates for labeling as well as numbered and lettered rows for tube identification. All are 9-3/4" x 4-1/8"x 2-3/4" high. Unloaded racks are stackable