Rancilio Classe 10 Water Valve Knob OEM-style water knob originally engineered for the Classe 10, but it interchanges cleanly with any commercial Rancilio machine using the same valve stem. The spring is included, so you're not stuck sourcing that separately. COMPATIBILITY Fits: Rancilio Classe 10 (original application); interchangeable with other commercial Rancilio models sharing the same water valve stem Replaces: Rancilio R_1253 INSTALLATION Simple DIY swap, pull the old knob off the valve stem and press this one on, no tools required in most cases. PRO TIPS If your old knob spins freely without opening the valve, it's almost always the spring losing tension rather than the knob itself, since this kit includes a fresh spring, replacing both together solves that intermittent "sticky valve" complaint for good.