Rion Co., Ltd. manufactures, sells, and maintains hearing instruments, medical equipment, sound and vibration measuring instruments, particle counters, and related parts and equipment in Japan. The company's audiological equipment includes hearing instruments, such as analog and digital BTE, trimmer digital BTE, in-the-ear ready and custom made, and analog body aid instruments, as well as waterproof hearing instruments; and medical equipment comprising audiometers and OAE screeners. Its sound and vibration measuring instruments include sound level meters, vibration meters, seismometers, frequency analyzers, microphones and accelerometers, recorders, and other products. The company's particle counters comprise air and liquid- borne particle counters, and viable particle counters. Its products are primarily used in the applications of environment-related administration, electronics, semiconductors, pharmaceutical, and food manufacturing industries. The company was formerly known as Kobayashi-Riken Seisakusho Ltd. and changed its name to Rion Co., Ltd. in 1960. The company was incorporated in 1944 and is headquartered in Kokubunji, Japan.