1. Product Overview UEF 204 2S four-bolt square flange bearing unit, matched with UE204-2S double set screw insert bearing. Equipped with double-sided 2S thickened NBR double lip rubber contact seals and two symmetric M6 set screws on inner ring. Spherical outer ring provides ±2.5° self-alignment to compensate shaft installation offset. Dual-layer rubber barrier effectively blocks dust, light mud splashes, water vapor and debris. Pre-filled long-life high temperature grease,