Hamp Synergy OEM High Performance Honda Oil Filter H1540-RTA-505 QTY=1 Large Originally designed for High Performance Type- R Engines Made by Filtech / Roki Includes a relief valve to keep oil circulating when the element is stuffed, or when the engine was turned on in very low temperature. High performance filter element for catching dust and carbon particles. Anti-drain back valve which is made from heat-resistant silicone rubber. This allows oil to circulate quickly when the engine is started.