This is the correct propeller for Nautique G-series boats (G21, G23, G25) with 2:1 gear ratio.
 
The OJ Evolution 3768-MF 4 Blade 17" X 17" LH 4-BLADE 1.25 BORE Propeller features a complete blade shape and pitch distribution redesign. Evolving from our successful WAKEPRO and V-4 series, the EVO propellers provide improved surf performance and efficiency. REPLACES 1770