Spirit Level 3 vial Machine milled Heavy-duty Length: 90cm / 36" Stanley Fatmax Spirit Level 3 Vial 90Cm | Sta143536 The levels in the Stanley FatMax heavy-duty box level range are machine milled on two sides to ensure accuracy on both sides, and have improved vial views for ease of use. The large centre vial is bridged to allow a continuous line to be marked on the workpiece. FatMax levels have an accuracy of +/- 0.5 mm/m on one face and +/- 0.7 mm/m on the other, which is covered under a five-year accuracy guarantee. The levels in the Stanley FatMax heavy-duty box level range are 6 mm taller and 6-9 mm wider than most other levels, and are also the heaviest in the relevant class, providing ultimate strength and durability.