The ACME 381 is a CNC-machined 4-blade Nibral propeller built for peak wakeboarding and waterskiing performance. With a 13.50″ diameter and 17.50″ pitch, it provides hard-throttle acceleration and clean wakes. Diameter: 13.50″ Pitch: 17.50″ Cup: .105″ Hub Length: 02.750″ Bore: 1.125″ Blades: 4 Rotation: Left