The finest stainless steel ball bearings. These are original equipment across all reputable reel manufacturers such as Daiwa, Shimano, Isuzu, and Abu Garcia. These come with a light grease applied direct from MinebeaMitsumi, so a thorough cleaning is required if they are to be used for baitcast reel spools. These are the bearings we use for our in-house builds and tuning services. We sell results, not hype.