1. Card Reader Function: When using the micro USB 3.0 port, this memory card case can be used as a card reader for reading small memory cards, compact flash cards, and storage cards, with a reading speed of up to 5 Gbps. 2. Holds 22 Types of Cards: This box is designed for carrying and storing memory cards, and can hold 22 types of cards, including 1 standard SIM, 2 Micro-SIM, 2 Nano-SIM, 3 compact flash cards, 7 storage cards, 6 small memory cards, and 1 card pin. 3. Waterproof: The blue waterproof material prevents unwanted debris and water from entering the card box, providing excellent protection for your memory cards. 4. Eco-Friendly Material: This memory card case uses environmentally friendly ABS material, which is safe and odorless, and can be used for a long time. 5. Portable: This waterproof memory card case is compact in size and lightweight, and comes with a handle, making it very easy to carry.