←Dead Level

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DEAD LEVEL · BULLSEYE VIAL · TWELVE MARKS · TRUE TO HALF A DEGREE · DEAD LEVEL · BULLSEYE VIAL · TWELVE MARKS · TRUE TO HALF A DEGREE · 3.5°7°10.5°

A bullseye level with twelve scribed marks. Tilt your phone to float the bubble into each ring, and hold it there until the ring closes. The last mark is dead centre.