Kapro 905-41-48 Condor Professional Box Level with Optivision Red and Plumb Site Dual View Vial, 48-Inch Length Optivision red horizontal vial creates highly visible red bubble edges, for exact placement between the reading lines and optimal vision in low light Tilted, tri-surface horizontal vial: direct line of sight for easy viewing and superior vial protection Plumb Site Dual-View vial with redEffect for a clear plumb view Reinforced profile with bridge at horizontal vial for increased toughness and marking a straight, unbroken line Finely milled surface