• Protection: Shields internal components like the battery, SIM card, and motherboard from physical damage, dust, and moisture.
• Aesthetics: Gives the phone a sleek and stylish appearance.
• Grip: Improves handling and reduces the chance of the phone slipping.

2. Material Types:

• Plastic (Polycarbonate or TPU): Lightweight and flexible, often used for budget and mid-range devices.
• Metal (Aluminum/Alloy): Premium look, better heat dissipation, commonly used in high-end devices.
• Glass: Offers a modern design, supports wireless charging but is more fragile.
• Leather or Vegan Leather: Used in luxury or flagship phones for a premium feel.

3. Features:

• Cutouts for camera, fingerprint sensor, charging port, speaker, and buttons.
• In some cases, includes antenna lines for better signal reception.
• May integrate wireless charging coils (in glass backshells).
• Comes in various finishes: matte, glossy, textured, etc.