Crystal clear vials readable in any direction with no change in accuracy tolerance. Spring steel hairline indicators in vials. Best frame strength-to-weight ratio. Removable rubber end caps for scribing in corners and for reading tight header and sill openings. Rubber end caps grip walls and do not leave marks. Metal Hang hole for storing level on site. Large comfortable rubber hand holes. Fast and accurate installations Strong, wide frame. Vials are guaranteed for life. BENT LEVELS VOID WARRANTY.