Magnetic stripe cards are simply PVC cards with either black or brown stripes on them made up of magnetic particles of resin. Brown stripes are generally low-coercively (Loco), while blank stripes are high-coactivity cards (HiCo). Coactivity is the ability of the magnetic tape to resist demagnetization. Magnetic stripe cards can both be printed and encoded in a printer / encoder equipped with a magnetic head. Magnetic stripe can be done on three tracks.