Double sleeving is a technique that collectors use to ensure the extra security of their cards. The card is inserted in a soft sleeve that fits perfectly, and then the soft sleeve is inserted into a hard-cased sleeve, meaning that it is impossible to damage. People who have rare cards that they are wanting to sell are strongly advised to take this route, particularly with cards that are worth thousands of dollars. The Ultra Pro Toploaders and Clear Sleeves utilize the double-sleeve method.