adhesive card holder

Common sizes include standard 3 × 5 inches (book cards), 3.5 × 4.5 inches (manila library pockets), and 4.13 × 4.13 inches (105 × 105 mm) index card pockets.

Package quantities vary widely. Examples include small multi-packs (3- or 6-piece sets), medium packs (around 30 pieces), and larger library-style sets such as 150 pockets sold as 3 packs of 50 or 200-piece sets (often listed as 100 pockets + 100 cards).

Some listings advertise RFID-blocking designs, using RFID-blocking material or metallic mesh linings intended to protect cards from RFID/NFC scanning and demagnetization.

They attach with self-adhesive or sticky backings to phone backs or phone cases. Some products can also be peeled and stuck to book covers, DVDs/CDs, and other surfaces designed to accept pockets.

Listings commonly state broad compatibility with many recent phone models and phone cases. A few listings warn that certain back coatings can prevent adhesion and suggest attaching the holder to a phone case instead.