The Spirit 1.0 propeller is designed to provide great torque because of its large diameter and low rotational speed, which is much more efficient than conventional gas motor propellers.  The propeller efficiency is optimized by using a variable-pitch design, which also keeps the propeller in high efficiency at a wider speed range.
 
Two-blade fiber-reinforced nylon propeller
Works with the Spirit 1.0 Plus/Evo
Dimensions: 11 × 5.8 inch / 280 × 147 mm