[Putershark]

Got a set of these at West Marine and had them installed the last time the boat was in the shop. For about hour of tech time (around 80 bucks) it was not worth the hassle to jack up the boat and clean out all the old grease myself

http://www.kodiaktrailer.com/content/view/27/83/

So far (several weeks now) they have held up very well even after several dunking into salt water with warm hubs (when most water gets inside) with no loss of oil. Now I have one less thing for me too worry about, and very easy to inspect

Highly Recommended for older trailers