Bel-Art F18860-1013 Stack Rack Test Tube Rack; 10-13mm, 72 Places, 9&sup1;/ x 4/ x 4&sup1;/ in., Polypropylene These sturdy, rigid racks feature interlocking end plates for secure stacking when loaded with tubes up to 10cm (4") long End plates have handles for easy transport; rows are numbered and lettered for easy tube identification White surfaces make color comparisons easy; sturdy and chemical resistant, these racks will not shatter or stain Steam autoclavable at 121 degree C (250 degree F) Top shelf height is 2-3/4"; rows: 6 x 12; tube size: 10mm-13mm