In 1952 Wilfried Schumann found that the earth has an electromagnetic field of 7.83 Hz that is vital to human health. Electromagnetic waves were later generated by PEMF devices and the FDA soon approved them as a therapeutic technology. Your mat may also have the PEMF feature. You will receive maximum benefits of EMF after 20 minutes of use once a day. After that, it automatically cycles off for 100 minutes to save power. The cycle then continues for another 20 minutes of PEMF followed by 100 minutes of it off. At any time you may turn the PEMF off and then back on to restart a fresh 20 minutes. Although 20 minutes is sufficient for maximum benefits, you can safely use PEMF all day. You will also receive a device to test PEMF at home. It is a small metal ball inside a plastic cylinder. Simply place the device near the mat with PEMF turned on and the metal ball will jump approximately eight times per second. This way you will always know if the electromagnetic field is on even if you don’t feel it. The PEMF has a range of 2 feet in all directions so any cover you may use will not block its effects. Individuals with pacemakers and pregnant woman should not use PEM