Does your Mercury or Yamaha outboard make a loud “CLUNK” when you shift it into gear? Does it make a chattering noise when in gear at lower RPM range? If so, you may benefit from an “anti-rattle” hub kit. Both Quicksilver/Mercury and Solas make effective anti-rattle hub kits for square hub propellers. We have had a lot of success reducing or eliminating the clunk and rattle, especially on the Yamaha 150s, 200s, as well as newer Mercury 4 strokes. They will fit in the following propeller systems: Quicksilver / Mercury Flo-Torq, Solas Rubex, Michigan Wheel XHS, Powertech Square Hub, and Turbo SQ-LOK.