Ventilators designed to reduce draught and muffle outside noises to the maximum. Daylight does not show through them. Simple three part assembly (cowls - liner - and internal louvre). Designed to be fitted with screws or mastic. All Draughtbusters meet BS 5440 : Part 2 : 2000 - BS 493 and BS 5871 : Part 3 requirements.
Fits through a 9" x 6" opening. Equivalent free area of min. 100cm2
Wall thickness : 280 mm to 330 mm (11" to 13").
For appliances up to 27 kW Net,(30 kW Gross).