A bearing is basically five parts. The inner race which touches the axle or bearing seat, the actual ball bearings which are the little balls between the inner and outter race, the outer race which is the external part of the bearing that is opposite of the inner race, the shields (there are two) which sit on top/below the ball bearings which"shield" the balls from attracting dust, and the C clip which holds the shields the shields onto the inner an outter races. The shields/c clips are often removed for cleaning and maintenance of a bearing, many players leave the shields off once removing them in order to facilitate easier access for later cleaning. I do this because I’m lazy, but it’s a two edged sword in the aspect that while it makes cleaning easier by access, it also makes it easier for dirt etc to enter the races of the bearing, this requiring cleaning more often.
go to the anatomy part
http://images1.wikia.nocookie.net/__cb20060528234309/yoyo/images/a/a6/Ballbearing.jpg the red part is the shield
Thank you so much! A great answer- you’re awesome.