Solas X-Prop Impeller - Pitch 14.5/17.5 ST-SC-XO 14.5-17.5 The SOLAS X prop qives you the most powerful propulsion in the water from an advanced design that incorporates a high compression hub and cambered blades. Enthusiasts looking for speed and acceleration from the novice to the professional, will be satisfied using this impeller. You can trust the harsh field testing of the X prop by Team SOLAS.