Scale with magnet for measuring the level of steel bones, etc. Easy to install just set it up. Strong magnets so there is no need to worry about it slipping. How to Use: (1) Attach the mug to the steel frame. (2) Reassembly (check the ruler with a transshot) (3) Ruler transition (reversible) *Please take a drop prevention treatment when using. Specifications: Base 2.5 inches (63 mm) φ Ruler 11.8 inches (30 cm) (JIS Standard Product); Quantity: 2