The Wister Blood Glucose Monitor is a small, portable device that is used to measure blood glucose levels. It is a reflectance meter, which means that it uses a beam of light to measure the amount of glucose in a blood sample. The Wister Blood Glucose Monitor is easy to use. Simply apply a drop of blood to the test strip, insert the strip into the meter, and wait for the results. The results will be displayed on the meter's screen in a few seconds.