The 6304 is an unsealed, premium-grade Single-Row Deep Groove Ball Bearing engineered for integration inside secure, enclosed mechanical housings. By entirely omitting side shields and rubber seals, this bearing offers unhindered access to its internal rolling elements, maximizing the flow of external lubricants. With precise metric dimensions of a 20 mm bore, a 52 mm outer diameter, and a 15 mm width, it is categorized under the medium-duty ISO 6300 series. This beefier structural profile provides significantly higher radial and axial load-bearing capabilities than lighter 6000 or 6200 series alternatives of the same bore size.