These fans are designed to be fitted in a window through a standard 260mm ø hole. A wall fixing kit catalogue No. 1301 is also available for through wall mounting which comprises of wall plugs, screws and a 400mm length of 9" diameter aluminum flexible ducting (when extended). WF230M Series extract rate 500m³hr, 138 litres per second. It comes with no quibble 2 year guarantee.