This is part number 1980A-SS. This is a great bearing buddy to use in salt water or freshwater since it is stainless steel and therefore will not rust. This bearing buddy measures 1.980 at its base, which is the portion that will be mounted into the outer face of your trailer hub. It is designed to be used in most 4 Lug or 5 Lug hubs that would otherwise use standard 1.98 Dust Caps. The blue indicator ring will protrude slightly to let you know when it's full, or recede when you need to add extra grease. Bearing buddies put a small amount internal pressure in the hub (about 3psi). When the hub is submerged, water cannot enter the hub because of this pressure. Its a great way to extend bearing life and service your bearings in-between hub re-packs. Bearing Buddy's help keep dirt and water out of your hubs and bearings.
The unique functions of the Trailer Bearing Buddy allow you to protect your wheel bearings from corrosion that could easily result if water were to enter the hubs chamber. This particular size is most common on standard 6 Lug Trailer hubs and can be used on Idler Hubs (non-braking), integral disc brakes, or brake drums.