Strong re-enforced frameFully sealed solid rail (six sided) extension eliminates deflection, and delivers the smoothest extension movement availableHand holes for easy handlingRemovable 1-5/8" stand-offs reach around bracesTop plumb vial is permanently positioned at eye levelFrame side opposite the stand-offs is a level measuring surface and straight edgeVials are guaranteed for life never to fog, leak or require adjustmentCertified accuracy in the top read position: 1/32" over 72"BENT LEVELS VOID WARRANTY