NPR-Riken 

NPR-Riken Corporation, operating with its subsidiaries, is a global manufacturer and seller of parts for automobile and marine engines, alongside various other industrial products. Their automotive offerings encompass critical components like piston rings for motor vehicles, motorcycles, and other internal combustion engines, as well as valve seat inserts. This division also produces a full spectrum of other engine components, including composite camshafts, cylinder liners, valve lifters, valve guides, rocker bridges, and valve rocker arms. Beyond vehicular applications, the company supplies piston rings for marine and industrial uses, sealing rings, and metal injection molded parts for sectors such as industrial machinery, office automation equipment, and leisure goods. Additionally, NPR-Riken manufactures compressor components and medical devices, including dental implants. The company's main office is situated in Tokyo, Japan.