This screwdriver set includes 1 sleeve and 4 screwdriver bits, designed specifically for dismantling V3, ZA3, BT20A PRO, and all Fosi Audio amplifier products. It's a professional repair toolkit aimed at assisting users in conveniently disassembling and repairing various audio equipment. The set features a variety of screwdriver bit types, covering common screws of different sizes and types to meet various disassembly needs. The sleeve design is tailored to better accommodate the disassembly operations of certain specific models, providing a more convenient and precise disassembly experience. This toolset is highly practical and suitable for use by professional technicians, audio enthusiasts, and DIY repair enthusiasts.