STABLE: High quality carbon steel hammer with stable performance. Strong magnet on the side for easy attachment to iron objects. ADJUST: Adjustable ranging for different construction situations. USAGE: Can be fixed on wood, masonry wall surface, safety lock can preven t accidental injury. DURABLE: High-quality nylon thread is easy to identify, wear-resistan t and durable, not easy to break. APPLICATION: Suitable for building line and wall vertical measurement. 1.POWERFUL USE: quick stabilization 310g bob for establishing a perfect vertical line or plumb bob, steadies within 6 seconds. 2.VALUE AND PRACTICALITY:Plumb bobs retractable - Through resistance adjustment, it can adapt to different specifications of plumb bobs (5oz-16oz), and can ensure that the balance can be quickly maintained. Just lift the plumb bob and the line will retract automatically. 3.FLEXIBILITY: Plumb bob with string includes positioning pins for wood or drywall, strong magnets for steel surfaces, and hooks for nails or studs. The locator wrapped in elastic material provides additional drop protection and a firm handle. The freely retractable positioning pin is safer, and can be retracted and positioned when not in use to preven t accidental injury. 4.PRODUCT SPECIFICATIONS: Universal magnetic plumb bob setter with 14.7ft. self-retracting line and 310g plumb bob. 5.Multi-occasion application: wood board, dry wall, gypsum board, steel surface can be used.