Strongest Magnets, flush mounted - Work Hands-Free. Spring steel hairline indicators inside the vials. Certified Level Accuracy in top read position: 1/32" over 72". Levels 59" and longer have a bridge over the horizontal vial for uninterrupted scribing and increased frame strength. Patented, epoxy-locked vials never need adjusting. Removable rubber end caps for flush measuring in corners. Patented red pads on end caps grip walls & flat surfaces. Prevents slipping on walls. Level accuracy guaranteed for life; vials will never fog, leak or require adjustment. Readable in every direction with no change in accuracy tolerance.