LW Scientific 75mm Microhematocrit Tubes/Mylar-clad Glass/Plain 200 vial. This is accomplished by the intentional design of the external surface of the tube which is porous to allow spontaneous clotting of blood or other biological matter. They are also useful in qualitative studies in which blood samples are collected in order to determine the hematocrit. These microhematocrit tubes come in a length of 75mm and a number of them are per vial with 200 per vial. Specifications for LW Scientific 75mm Microhematocrit Tubes/Mylar-clad Glass/Plain: Manufacturer: LW Scientific Capacity: 75 ml Features of LW Scientific 75mm Microhematocrit Tubes/Mylar-clad Glass/Plain: Microhematocrit tubes 75mm 200 per vial Package Contents: LW Scientific 75mm Microhematocrit Tubes/Mylar-clad Glass/Plain LW Scientific CNT-HTMC-PN77: 75mm Microhematocrit Tubes/Mylar-clad Glass/Plain 200 vial