SmartMedia cards came in two formats, 5 V and the more modern 3.3 V (sometimes marked 3 V), named for their main supply voltages. The packaging was nearly identical, except for the reversed placement of the notched corner. Many older SmartMedia devices only support 5V SmartMedia cards, whereas many newer devices only support 3.3V cards. In order to protect 3.3V cards from being damaged in 5V-only devices, the card reader should have some mechanical provision (such as detecting the type of notch) to disallow insertion of an unsupported type of card. Some low-cost, 5V-only card readers do not operate this way, and inserting a 3.3V card into such a 5V-only reader will result in permanent damage to the card. Dual-voltage card readers are highly recommended.