Changsha Haochang Machinery (HC Enginepart) manufactures piston rings with diameter coverage from φ30 to 800 mm, covering large-bore two-stroke marine diesel engines including the MAN B&W S80ME-C (800 mm bore). This range also encompasses smaller MAN B&W two-stroke models such as the S50MC-C (500 mm), S60MC-C (600 mm), and S70ME-C (700 mm). All rings are produced to OE specifications under the ISO 9001:2015 quality system, and HC can develop rings from customer drawings or physical samples. For very large bore engines, HC recommends submitting the original ring sample or drawing to ensure exact dimensional and material matching.