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/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.