Premium corrosion resistant brass splinesReduce prop replacement costs by up to 50%Each kit contains a hub, thrust washer, and other hardware for installing Turning Point Aegis, Express Mach3, Mach3 OS,Mach4, and Hustler propeller hosings on most engines w/4.25" or 4.75" gearcaseAlso used as a hub upgrade to fit Solas Rubex, Michigan Wheel XHS, and Mercury FloTorq propeller housings