This assembly is designed specifically for 3.5 x 7 ga. tubing as an alternative to using .300 wall tubing. The bearing is one of our most highly recommended bearings. It is ideal for heavy loads and long service life in extremely dirty environments including foundries and concrete plants. A hole through the inner race allows the bearing to be regreased through the axle. Bearings that are regularly regreased can withstand very high levels of debris without damage. Metal shields deflect large particle debris and protect a rubber contact seal that is very effective against fine dust and other small particle debris. The seals add rotational drag and are not recommended for gravity applications with light product. Recommended for powered applications where roller resistance is not an issue and the roller is constantly rotating.