4 bolt flange bearings are mounted within a flanged bearing housing and are preferred when the bearing mounting surface is perpendicular to shaft access. 4 bolt flanged ball bearing units have a square shape with four holes for mounting. The four hole design accommodates higher loads than a two or three bolt flange. At Bearings Direct, we offer waterproof 4 bolt flange waterproof units that feature a thermoplastic housing and stainless steel insert bearing that makes them ideal for use in applications that require a clean operation. For more information about 4 bolt flange waterproof units, contact us today!