If you're a crazy maintenance type of person, this kit might not be something you need. For me, I have a few bikes and sometimes they're not always in my riding rotation and might sit for a spell. This is where I found a problem. If I rode a bike in wet conditions or washed a bike with that taboo power washer and just parked it without doing a full prep before I let it sit, I paid the price later. Water got into my rear axle, and when I removed it after some time has passed there was corrosion on the axle. I was able to wire wheel the crud off, but by then the coating was gone and bare metal was now exposed. Even if an axle is greased, portions can scrape off when installed. If water or crud gets in, the result could be a corroded axle or possibly trashed bearings.With this issue and knowing the rear wheel had been neglected, I decided to do a rebuild. Instead of just using standard parts or a rebuild kit, I discovered the Pivot Works Waterproof Wheel Collar Kit. The bearings and seals are stock-style aftermarket components, but the key to the kit is the O-ring wheel spacers. Why hasn't anyone thought of this before? We worry so much about the seal that the wheel spacers go into but never about the non-watertight area between the wheel spacer and the axle. Yes, it is a tight fit but not waterproof or water-resistant. The Pivot Works units have an O-ring on the inner diameter of the spacer that is designed to seal off the inner wheel when the axle is pushed through.