• Mechanical counting: No electricity required, stable and drop - resistant, for long - term use. • Competition - grade professional bearing: High - speed steel ball bearing, smooth rope rotation without jamming. • 5mm thickened solid rubber - coated steel wire rope: Strong and wear - resistant, no rope fluttering or knotting. • Gravity large rubber ball: Diameter 60mm, weight 120g, double the fat burning, efficiency increased by more than 1 time. 360° High - speed Bearing, Smooth Without Stuttering High - speed Universal Steel Ball Bearing High - speed Silent Design The service life of the bearing is up to 10 million revolutions HIGH - SPEED SILENT DESIGN