The Bahco 416 Series Spirit Levels are made from lightweight aluminium with a 1.4mm wall thickness profile. They have unbreakable vials filled with liquid resistant to UV light and extreme temperatures. Two lines in each side of flat vial for easier use. The set contains the following sizes: 1 x 416-600 Spirit Level 1 Vertical & 1 Horizontal Plumb1 x 416-1200 Spirit Level 1 Vertical & 2 Horizontal Plumb1 x 416-1800 Spirit Level 1 Vertical & 2 Horizontal Plumb Specification: Measuring Accuracy: in the normal position 0.029° = 0.5mm/m, overhead measurement 0.043° = 0.75mm/m