The vacuum system consists of a double-pointed needle, a plastic holder or adapter, and a series of vacuum tubes with rubber stoppers of various colors. The colors indicate the type of additive present. Another kind of holder is available, which allows resheathing of the needle with the holder after venipuncture. Blood collection using the evacuated tube collection system will produce the best blood samples for analysis by the laboratory. The blood goes directly from the patient into the appropriate test tube.