タイトルまたは説明

Showed a circular rolling body symmetry axis and a cross-section in any plane perpendicular to its axis of.
 Our steel ball products, with the spec. of 0.5mm**5mm intervals and ******0 standards, include bearing steel ball, carbon steel balls, stainless steel balls, copper balls and other material metal balls. Our products are mainly applied to the bicycle, manpower-operated vehicle, light, machinery , spinning and weaving, measuring, chemical, war and aviation industries..