The SERTO connecting nut, marked with code number K 87163, is a precision-engineered fitting used to securely join fuel piping in the ZV40/48 engine’s fuel delivery system. Manufactured to tight tolerances, this nut ensures leak-free connections even under high pressure, preserving the integrity of the fuel line and minimizing fire risk. Its compatibility with SERTO’s compression fitting system allows for quick installation and reliable sealing. A critical component in maintaining fuel system efficiency, the connecting nut supports safe, continuous engine operation in demanding environments.