The cats a$$.I had a set of moose on one of my KTM's and the seals never grooved them a bit like the stock aluminum pos so the bearings stayed happy.The downside of these was the inside diameter was slightly off so you had to tap the axle fairly hard to get in and and out.On my other ktm,I got a friend to machine the stock unit down slightly and press on a stainless sleeve then machine this to the original dimension.The result?Perfect.No wear,lightweight and fit like stock-because it was.It's a mod that is coming soon on the berg but I'd sooner have the latter setup so am in the process of harassing said friend as we speak.