1" Shaft Coupler Nut & Key Kit – 3/4-10 Nyloc LocknutKeep your drivetrain secure with this 1" shaft coupler nut and key kit from Marine Hardware. Designed for marine and underwater applications, this kit includes a corrosion resistant hex nylon insert lock nut (nyloc) and a precision rectangular shaft key to help maintain a tight, reliable connection between your coupler and shaft. The nylon insert resists vibration looseningideal for high load, wet, and high vibration environments. Fits shaft size: 1"