innovated horizontal cylindrical level - easy visibility from all angles double rings in spirit level - outer rings for 2% slope more pronounced fluorescent liquid for better visibility of the bubble in the sun and in poor lighting conditions spirit level with two vials accuracy 0.5mm/m = 0.0285° wall thickness of ALU profile 1.5 mm, anodized abrasion-resistant surface magnetic version - strong magnets, for work in locksmithing, installing metal frames, etc. spirit level is resistant to operational impacts 10 year warranty on spirit levels, EACH PIECE ELECTRONICALLY TESTED