Greenwood 4000S 400mm UPVC White Front Operation Trickle Vent, Slot Vent SFW
Manufactured from high quality UPVC and suitable for all window types. Fig. 1 provides 2700mm2 equivalent area (E+W), 4000mm2 free area (S). Fig. 2 provides 3200mm2 equivalent area (E+W), 5400mm2 free area (S).