This is a near perfect card, that is, one with little or almost no jitter. This card is ideal for testing the level of jitter inherent in a magnetic card reader. This inherent jitter is caused by motor, gear, belt, and bearing noise, as well as head vibration and imperfections in the read circuit. Because the card's jitter is virtually zero, all jitter measured from the reader (checked by a timing analyzer or jitter tester) is contributed by the reader itself.