Coercivity is a measurement of the amount of energy it takes to change the polarity of a magnetic field. Since information on magnetic stripes is stored as a pattern of positive or negative magnetic fields, coercivity also becomes a measure of how long an ID Card’s magnetic stripe can retain the information that has been encoded within it.

Oersteads (Oe) are the units used to measure coercivity. Low coercivity is defined as 0-300 Oe. High coercivity is 300-3000 Oe. Hi-Co ID badges are actually encoded at a level of 2750 Oe.

Because it takes a stronger magnet to change its unique pattern of magnetic fields, information stored within a hi-co magnetic strip will not be degraded as quickly as information stored on a low-co magnetic strip.

In other words: hi-co ID cards work longer than lo-co ID cards.

Of course, they also cost more.

Culprits responsible for erasing information from identification badges include refrigerator magnets and demagnetizers used by stores to prevent shoplifting. Low-coercivity stripes on ID cards are usually brown, high-co stripes black. ID card printer lines made by Fargo that print and encode magnetic stripe ID cards include the DTC, Pro-L, and HDP.

ID badge printers are usually marketed in both a standard version – which is unable to encode magnetic stripes - and a version that has a magnetic stripe encoder built into it. Some manufacturers of ID card systems, realizing that client needs can change, sell ID card printers that can have encoder modules added to them later.