Overhead Door Corporation's side-folding full closure grilles are ideal for applications that require a secure barrier against theft and debris, such as retail applications in malls and airport concourses. The Full Closure side folding grille product line includes four panel materials: perforated steel, clear polycarbonate, tempered glass and aluminum. All four models are available in both standard-body and wide-body versions. Series 675 Ventgard™ — painted perforated steel for full ventilation. Curtain: 6-5/16" (160mm) standard-width, 18-gauge with 3/16" perforated holes on staggered centers that slide into aluminum hinges. Panels are framed by min. 4" (102mm) high aluminum bottom plates and 5-1/4" (133mm) high aluminum top plates. Visibility: 51% of 4-3/4" (121mm) viewable area.