Adjustable lengths 80MM, 120MM, and 140MM extension lengths let you adapt to different drilling tasks and reach tight areas with ease. Locking mechanism Each interface includes a secure locking mechanism with magnetic support to keep screwdriver bits firmly in place during operation for safer, more reliable driving. Design innovation An outer sleeve and bit shaft separation provide a strong grip while allowing smooth rotation of the screwdriver head for comfortable onehanded use. Guide sleeve functionality The selfretracting guide sleeve covers long screws, adds stability while driving, and protects your fingers from potential injuries. Use scenarios Assembling furniture and cabinets where screw length varies and access is limited. Installing long screws in wood or metal projects that require precise alignment in constrained spaces. General home maintenance and DIY tasks that benefit from variable length extensions and onehanded operation.