STAR SWR Fittings – Coupler 110mm (Ring Type) This is STAR branded SWR Fittings – Coupler 110mm (Ring Type), is used as SWR fittings in SWR drainage system for changing the direction of pipe line. This STAR SWR Fittings – Coupler (Ring Type) is available in 75mm to 110mm sizes and are made as per international standards.