DLT-2.5 Professional dental loupes or surgical loupes as they are often called. The DLT-2.5 model has a working distance of 380mm or 14.96inches. These are comfortably designed with light weight but durable sport glass frames and adjustable flip up design. 2.5x is the most recommended magnification for wide expanded field of view and deep 5.5" depth of field for easy use and viewing. Or sport frames have poly-carbonate (non Rx) lenses for safe working and easy cleaning and titanium and reinforced resin side arms for strong light weight design. Galilean lens are tri-coated anti-glare, fog,and scratch resistance. Silver and black sports frames designed to fit most med to large head sizes and shapes.