Washer SST Type may vary by manufacturer, visit www. rubexprops. com for current application information. For Solas Dual Prop and B3 installations, front and rear propellers must both be manufactured by Solas. Also, they must be made of the same material: either aluminum or stainless steel but not both. Special tools may be required to install Dual Props. Please consult OEM manual for proper installation and torque specs. Disclaimer: Pitch estimates and propeller selections made by this prop finder are provided only as a general reference and may not be correct for specific boats under actual boating conditions. By using this prop finder, you agree that the Solas Science and Engineering Company, Ltd, its dealers and other host entities do not accept any liability and are not responsible for harm to persons or property, damages or costs caused by the installation, handling or use of an indicated propeller or hardware. Refer to your engine's Owners Manual for important safety precautions when installing a propeller. A new propeller's hub and blades must be checked for sufficient lower unit and trim tab clearances before use. Engine manufacturer recommends greasing the propeller shaft every 12 months. Wide open throttle RPM, with boat on the water in forward gear under normal loading conditions, should fall within the range that is recommended by the engine manufacturer and not exceed the recommended maximum.