High coercivity magnetic stripe cards are generally used for applications when the information that is encoded onto the mag stripe is intended to remain and be used for long periods of time. 2750 oe (abbreviation for oersted, which is the unit of measurement for magnetic field strength or intensity) refers to the amount of magnetic strength used to encode the information - the higher the oe, the higher the likelihood that the information will remain on the mag stripe of the card, even when it comes in contact with other strong magnetic fields, such as a cell phone or another mag stripe card.
A Lo-Co card on the other hand, is ideal for short-term use cards, such as a hotel key card.
High-Co cards can be easily distinguished by a black mag stripe, while Lo-Co cards have a lighter, more brownish colored mag stripe.