Rugged and reliable, Cat® Controllable Pitch MPP HUB feature the first hub system in the shipping industry where the moisture content is continually monitored. Developed for heavy-duty applications, Cat Controllable Pitch MPP HUB have a pitch-setting hydraulic servo cylinder in the hub. And when we say heavy-duty, we really mean it – from the optimal propeller blade sealing system and stiff hub body to the largest possible bearing surface for the blades. Not to mention the unique lubrication system with continuous monitoring of the moisture content in the oil. You can rest assured that the entire propeller system is protected as well as the environment.