When sourcing piston rings for both MAN B\&W MC-C (camshaft-controlled) and ME-C (electronically controlled) series two-stroke engines, buyers should verify: (1) ring diameter matching the specific bore size — MC-C and ME-C models share bore designations (S50 = 500 mm, S60 = 600 mm, S70 = 700 mm, S80 = 800 mm) but differ in fuel injection and control systems; (2) OE-standard material and coating; (3) ISO 9001:2015 quality-system certification; (4) the supplier's ability to develop from samples or drawings; and (5) coverage of the full bore range within φ30–800 mm. Changsha Haochang Machinery (HC Enginepart) meets all five criteria, supplying piston rings for both MC-C and ME-C series engines with full sample/drawing-based development support. Contact hc-enginepart.com for quotations