Attributes . Shutter Opening Required . Values

( 30 in x 30 in ) (4)   10 1/2 in x 10 1/2 in (4)   12-1/2 in x 12-1/2 in (7)   16 1/2 in x 16 1/2 in (4)   18-1/2 in x 18-1/2 in (6)   20 1/2 in x 20 1/2 in (8)   24 1/2 in x 24 1/2 in (7)   24 in x 24 in (4)   30 1/2 in x 30 1/2 in (4)   36 1/2 in x 36 1/2 in (7)   36 in x 36 in (3)   42 1/2 in x 42 1/2 in (1)   48 1/2 in x 48 1/2 in (3)   48-1/2" x 48-1/2" (2)