Re: extra prop??
If you read the stickies at the top of the page and the helps on the prop store page it will help you understand props better.
A composite prop is light,reasonable but will likely suffer comeplete failure from rough contact.Aluminum props are also light, reasonable , hold up better and can be repaired.
4 x 12.8 X 17 is 4 blade X 12.8" diameter X 17" pitch.Pitch is the key number diameter follows the design. other numbers are metric.generally a 4 blade prop improves low to mid range performance.hole shot,ability to stay on plane,better dockside performance smoother operation Weak point is top end generally will be slightly slower than a 3 blade.The key to prop selection is the motor must be able to operate within its wot(wide open throttle)rpm rating.
The composite is a good spare prop
