A small-size cylindrical cylpeb for top-up charging in fine and ultrafine grinding chambers. Its low mass and high specific surface create dense contact points with the charge, holding fineness at a lower ball load and reducing over-grinding and liner wear. Material and heat treatment match the larger cylpebs, with vanadium-titanium microalloying balancing hardness and toughness. Supplied at Φ25×30 mm for cement finish grinding, slag powder and chemical raw-material milling, in bulk bags or steel drums.