these are not a durable bearing. and are often mis-boxed. i no longer depend on this brand for my race machines.
I purchased these bearings before I left for a trip out west and the bearings were the wrong size and did not fit in my bike. The bearings were not greased on the inside of them. The bearings were made of poor quality as well as the shaft. This almost ruined my trip. I would not recommend the "all balls bearing" kit.
I like this kit since it comes with bearings that are wider than the standard bearings. I also like the fact that the bearing inner race is 20mm and this is what the axle rides on instead of the collar that the stock KTM bearing setup uses. I always pull off the dust covers on new bearings and clean the bearing out, then repack with a really good waterproof grease. I ride in some gnarly terrain and wet conditions out here on the Olympics in the PNW. We will see how they hold up.