MechPort 2 Pack Flexible Shaft Coupler 4 mm to 5 for RC Boat Shafts

- Compatible with RC boat motors using 4 mm shafts and 5 mm propeller shafts; fits model marine drive lines for smooth power transfer during lakeside runs and bench testing. - Flexible shaft coupling with aluminum alloy hubs and rubber insert helps absorb minor misalignment and vibration; compact 24x10 mm body with 4 mm and 5 mm bores supports steady rotation and reduces drivetrain noise. - Vibration damping connector links brushed or brushless motor to prop shaft, cushioning start‑up shock and throttle changes to help protect gears and bearings in choppy water or tight maneuvering. - Simple fitment: direct 4 mm to 5 mm connection reduces the need for extra adapters; verify straight alignment and clearance; suited for workshop builds, club repairs, and on‑site tuning sessions. - Model marine drive coupler intended for RC boats on ponds or pools; also useful for small robotics and DIY motion projects needing a compact, flexible link between shafts of different diameters.