Complex sentence: Proximity cards typically have a range of around 5 cm (2 inches) for reading, so the user often leaves the card inside his or her wallet or purse, and simply holds the wallet or purse near the reader.
Split into simpler sentences: Proximity cards typically have a range of around 5 cm (2 inches) for reading. The card can often be left in a wallet or purse, and read by simply holding the wallet or purse near the reader.