The 521 Series is a sectional aluminum door appropriate for environments where maximum light infiltration and/or visual access is required.  Designed to fit openings up to 26´2" (7976mm) wide and 20´1" (6121mm) high, the 521 Series features a wide, 2-3/4" (70mm) center stile, a 3-3/4" (95mm) or 4-1/2" (114mm) bottom rail.  Like the 511 Series, the 521 Series is available with a variety of glazing choices, finishes and special options.