Air extraction unit benchvent bv300s d this air extraction unit uses a flexi duct to carry away extracted air either via a standard domestic vent or simply placed through a partially opened window making the unit very portable and convenient the unit can be used in one of two positions either upright for 3d items such as models pcbs etc where they can be rested on the surface and where solder fumes and general solvent and gas extraction is performed the second position the unit can be