ESI Tap-changer filter units remove moisture and particulates in the insulating oil, maintaining electrical properties and reducing arcing during contact break. Cost savings in maintenance, spares and a significant increase in system reliability soon recover initial installation costs.Stainless Steel construction, pipe and fittings ensure maximum filter life. These units have been installed on a wide range of tapchanger switches on transformers ranging from 33Kv to 500Kv.