4 inch conveyor chain trolley used with 4 inch conveyor chain. Trolley wheel is bolted to the trolley . It is usually for carrying weight under , trolley material by 20Cr, conveyor rivetless chain material by 40Cr through hardened with hardness HRC 38-42. The X458Chain is specifically designed for overhead conveyor service, popularly enjoyed by customers in USA, Europe, Korea and Australia. X-458 chain components are drop forged from high-strength steel, precision forged and finished. All chain parts are hardened to increase resistance to wear, corrosion, abrasive action and shock loads.