Proflow Coolant Filter, Inline with Cap, Billet Aluminium, Polished, 1.500 in. Inlet, 1.500 in. Outlet, Kit - PFEWF150PPart Number: PFEWF150P Our billet radiator water filter is great for collecting any unwanted debris circulating the cooling system. It has a 100 micron filter element to trap debris without restricting fluid flow and comes with standard 1. 50" hose size fittings. These can also be unscrewed and changed to other sizes if necessary (adaptors sold separately).