The SM 4531 is a premium, Original Equipment (O.E.) Grade Self Starter Rocker Assembly (Brush Holder) specifically designed for the Piaggio Ape BS6 (Bharat Stage 6) series. Identified by the 3668 series designation, this assembly utilizes a robust Bosch-style (B.TYPE) architecture with a high-efficiency 4-brush configuration. It is precision-engineered to meet the strict electronic and mechanical requirements of modern BS6 fuel-injected engines.