The material of the briefcase

Including both fabric and components.
Fabric should usually have characteristics such as wear resistance, tear resistance, and waterproofing. Popular ones include Oxford nylon fabric, polyester short fiber canvas, cowhide and genuine leather PU simulation leather, etc.
The components include waist buckles, all zippers, shoulder and chest strap fasteners, cover and body fasteners, external strap fasteners, and so on. These buckle materials are usually metal and nylon, and you should carefully choose them with your eyes when purchasing.