This is a replacement part/upgrade for the KegLand Cannular Canning Machine. Specifically, the ball bearings that aid in the rotation of the turntable. (e.g. where the can sits.)
The ball bearings and washers are made of 402 stainless steel.
When you purchase the Cannular canning machine they come with standard carbon steel bearings. The standard carbon steel bearings need to be cleaned and oiled regularly but due to the high hardness of the steel grade, they do last a very long time. Stainless steel is a bit softer but it has better corrosion resistance and is ideally suited to customers that do not want the hassle of regularly cleaning and applying oil to the bearing stack.