High Quality: These durable screwdriver bits are made of CRV steel, whose hardness can reach HRC52-56, ensuring long-lasting use. Precise Design: The precision screwdriver is designed with a 3-level adjustable post and a magnetic head for easy operation. The handle is non-slip and comfortable to hold due to its ergonomic design. Included 30 screwdriver bits. Portability: The plastic storage box holds the screwdrivers, easy to carry anywhere and fixes each screw head on the holder. Multifunctional: The adjustable screwdriver set can be used for individual and professional purposes, including repairing phones, TVs, computers, laptops, watches, air conditioners, glasses, cameras, printers, household appliances, and other electronic devices.