These racks hold 143 vacuum-type syringe tubes: 80 tubes 12.7mm (1/2") O.D. and 63 tubes 16mm ( 5/8") O.D. up to 102mm (4") long. Tubes are suspended in channels by colored stoppers providing instant visual identification. One or two channels may be left open for stacking blood samples in sequential order as they are taken, for later numbering. Three side openings for needle holders make this a complete blood drawing accessory. Steam autoclavable at 121°C. Measures 48.3 x 15.2 x 21.6cm.