A sleeve for a smartphone is a protective cover designed to encase the device, shielding it from scratches, dust, and minor impacts. Typically made from materials like fabric, leather, or neoprene, these sleeves often feature a simple design that allows for easy insertion and removal of the smartphone. Many sleeves are lightweight and portable, making them convenient for travel or daily use. Some may include additional features, such as pockets for cards or cash, while others focus solely on protection. A sleeve can be a practical accessory for anyone who wants to keep their smartphone safe and secure.