The 691-2RS represents the pinnacle of miniaturization in rolling bearing technology. Designed for ultra-precision assemblies where installation space is extremely restricted, this single-row bearing features a 1 mm bore, 4 mm outer diameter, and a 1.6 mm width. The "2RS" designation indicates high-quality contact rubber seals on both sides, providing superior protection against moisture, fine dust, and environmental contaminants compared to shielded versions. Pre-filled with premium synthetic grease, the 691-2RS ensures stable, low-noise rotation for sensitive electronic and medical micro-devices.