The entire throat height or air gap of a laser gauge's C-frame enclosure constitutes its accurate measurement range so that any material passing at any height through the air gap will be accurately measured. The laser gauge has at least one laser and usually two lasers housed in an enclosure with at least two arms that are spaced apart for receipt of a target surface in the air gap between the arms. The gauge has a first enclosure barrier attached to a first one of the enclosure arms at a first boundary of the air gap. The first enclosure barrier is positioned away from the laser at or beyond the gauge's proximal measurement limit. A second enclosure barrier is attached to a second one of the enclosure arms at a second boundary of the air gap. The second enclosure barrier is positioned away from the laser at or nearer than the gauge's distal measurement limit.