Turning Point - Express Mach4 Stainless Steel Propeller - Left Hand - 4-Blade - 13.25" x 17" - EX1/EX2-1317-4L - 31431740. Now manufactured in our Industry leading TP17 stainless, the Express Mach4 series is perfect for any application that demands enhanced acceleration, cornering, and load carrying capabilities. This prop series is ideally suited for watersports, sterndrive boats, tri-toons, bay boats, and any vessel that can use stern lift. It is our best upgrade of older stainless designs from the 70's, 80's, 90's, and '00's, and will outrun most newer props, including five blade ski props.. Specifications:. Diameter (Inches): 13.25'. Material: Stainless Steel. Pitch: 17'. Brochure (pdf)