The Stihl FS 45 trimmer uses two different types of caps depending on the part of the tool you need to service. The fuel tank cap (Part #4128-350-0505) is a durable black plastic cover engineered to seal the fuel reservoir securely, preventing leaks, stopping evaporation, and maintaining the necessary pressure for smooth two-stroke engine performance.
The Stihl FS 45 trimmer cap typically refers to the fuel tank cap (OEM part # 4128-350-0505). This genuine black twist-off plastic cap includes a built-in sealing gasket and is designed to create an airtight, leak-free seal on the engine’s fuel reservoir. It prevents fuel spills and protects the engine from debris