Bearing Buddy 42304: size is 1.398″.. Bearing Buddy Stainless Steel Trailer Wheel Bearing Protector – 2 PackThe Bearing Buddy prevents wheel bearing failure on boat, snowmobile, ATV, RV and utility trailers. It eliminates bearing repacking and keeps water and dirt out of hubs and bearings. Features stainless steel components and is easy to install.You can choose to purchase your set with the Bearing Buddy bra which is a vinyl cover that fits over the Bearing Buddy to contain excess grease and keep it off tires and wheels.You also have the option to purchase your set with the grease level indicator which allows for quick positive visual check for lubricant level and internal hub pressure.