These 4 ml Serum gel non vacuum tubes are supplied by MB Lab Consumables, a leadding brand in the field. These vacuum tubes are used routinely by clinicians, doctors and researchers alike. These 4 ml vacuum tubes contain a thick layer of serum that separates the gel in the test tube. This allows for complete isolation of the serum and blood cells. As a result of this, the blood cells are unable to come in contact with the serum. These tubes are designed and processed in such a manner that they allow a really quick and efficient serum and blood clot separation. The gel present is inert and if the tube is to be centrifuged, the gel ends up between the clot and the obtained serum. The tubes themselves are made from medical grade, high quality material. They are 13 x 75 mm in size. Furthermore, they are sterile and disposable. Complete clot retraction in these tubes takes two hours at most. They are durable and have high temperature resistance. These tubes have a yellow coloured cap . These tubes have a shelf life of two years and it is recommended to store them between 4 to 25 degrees Celsius.