BMI High precision spirit level features magnification vial bubbles that move 5x faster than those of ordinary levels, so is effectively 5x more accurate. Therefore, inaccuracies can be recognised much sooner- and much better. BMI-round bubble for glare-free effect. 0.3 mm / m mounting accuracy of vials in normal position. BMI 4-chamber profile, the most resistant profile in the market. Effective additional protection through shock-absorbing rubber endcaps.  This level is highly accurate and is designed for when the highest level of precision and accuracy is required – Do NOT use this on brickwork, it will blow your mind!