It's WWI propeller. S1 V1 is WWI Non Weathered vintage propeller. S1 V2 is WWI Weathered vintage propeller. The propeller has good flight performance and high efficiency. Both scale and performance are considered.
Hand crafted propellers are designed for the best performance and efficiency in both gas and electric applications. CNC designed and manufacutured. Manually pre-balanced and pre-drilled. Hand finished to perfection.