Spirit Level Aluminium HVP Magnet Strong aluminium profile measuring 49x23 mm and weighing 650g/m, with magnets on the underside. Crush-proof block vials that are highly transparent and durable. Horizontal vial with a magnification lens and luminescent reflector. Features The radius of the vial is 200 mm, giving a sensitivity of 10 mm/m.Tolerance in normal position is ±0.5 mm/m, upside down ±0.75 mm/m.The liquid in the vial is a low viscosity coloured oil mixture that gives the bubble optimal freedom of movement.Highly resistant to ultraviolet light and temperature fluctuations.The anti-static properties of the liquid means that the bubble is not affected by static electricity.