Steel outer ring with Silicon Nitride ceramic balls material 10x19x5 mm IDxOdxT Cocok utk dipasang di gowes / mountain biking Bersepeda menjadi jauh lebih ringan ; sangat terasa di RPM tinggi Sudah berikut tutup karet (end seals) supaya debu dan kotoran tidak gampang masuk high temperature strength. superior thermal shock resistance. excellent wear resistance. good fracture toughness. mechanical fatigue and creep resistance. good oxidation resistance.