Wind driven radon extractor with 112mm pipe socket. An adaption of the Flettner Ventilator used on commercial vehicles worldwide. Flettner are the world leader in the design and manufacture of wind powered ventilators. The unit fits directly onto a 4″ soil pipe socket. It is being used widely as a passive radon extractor by county councils in Ireland, the benefit being that there is no electrical connection required and no electricity consumption. This is the most efficient passive extractor available and has been proven to reduce radon levels by up to 75%. It works particularly well in new buildings which have existing stand-by sumps installed.