Rion Co., Ltd. is a Japanese precision equipment manufacturer specializing in measurement and medical technologies. Headquartered in Tokyo and founded in 1944, the company today focuses on three core businesses: particle counters, medical equipment, and environmental measurement instruments. Rion’s particle counters are used to monitor air and liquid cleanliness in industries such as semiconductors, pharmaceuticals, and other high‑purity manufacturing environments. Its medical equipment division develops and supplies hearing aids and audiological testing systems that serve hospitals, clinics, and hearing care professionals. In environmental equipment, Rion provides sound level meters, vibration meters, frequency analyzers, and related systems used in environmental administration, industrial quality control, and occupational noise and vibration management. Through these specialized product lines and associated maintenance and calibration services, Rion Co., Ltd. plays a significant role in supporting regulatory compliance, product quality assurance, and healthcare diagnostics in Japan and global markets.