It seems Revain has some confusion about thrust bearings. These bearings appear fixed at first, but can be significantly realigned during installation. I would say that there is a 10-15 degree angle deviation, once the gimbal goes through the bearing, the orientation can be changed slightly. The cast iron hardware around the bearings feels well made and much more durable than the kit they replace. After installing it on my old 1" driveshaft for my snow thrower, I lightly lubricated the bearings through the included mirrors and was happy to see the grease seeping into the bearings and out of the bearing seals. I don't know for how long they will last my second to last set was factory sealed with no mirrors and has lasted many years.