STABILA levels are unparalleled with regard to their accuracy and dependability. The secret - the vials made of block acrylic glass are firmly epoxy-locked in the frame. A perfect system. The vial is firmly cast in the high strength aluminum frame with non-shrink epoxy. No re-adjustment, no realignment, no tensioning against springs made of steel or fatigued plastic, no welding or clamping stresses. Just as accurate after 10 years as on the first day. Features Type 196. Our number 1 selling frame design. Certified Level Accuracy .029 degrees - 1/32in over 72 inches - 0.5mm per meter right-side up or upside down. Every level is electronically adjusted, then accuracy inspected and certified. Vials read the same in all positions. Bright easy to read vials will not leak, break, fog or require re-calibration. Level accuracy guaranteed for life.