Every Rubex boat propeller has a rubber interchangeable hub system. It is designed to eliminate chatter and vibration that competitive hub systems are prone to. Being rubber, the Rubex hub has no plastics to deteriorate. It can deflect 10% for softer shifting and to reduce prop shaft shock when the propeller strikes a submerged object. The Rubex hub will not spin in the propeller. Each Rubex Hub Kit comes with the hardware needed to install the propeller on the prop shaft. Unlike competitive hubs, the prop nut does not require periodic re-torqueing on a Rubex propeller system. The Rubex 4 propeller offers stronger blades and better performance, including great acceleration and mid-range performance, as well as great stern lift and handling. 12.75" Diameter. 17" Pitch. Right Hand Rotation.