Thermostatic or manually controlled, 14 leaf type shutters, r.H. Control, 28.375 in. H, 28.500 in. Lg, sixteen 1/4-20 unc thd holes around outer flange, 3 top and 3 bottom holes spaced 7.125 in c to c, 6 holes on each side spaced 6.500 in. C to c, with end holes spaced 1.188 in. From top and bottom to hole center