RMD Instruments, LLC (RMD) is a privately owned medical device company, specialized in the design and manufacture of Navigator global positioning systems and other medical instruments. Its Navigator global positioning system is used in the sentinel node mapping procedure. It also offers a range of probes including, Standard Lymphatic Mapping probe, for lymphatic mapping of malignant melanoma and breast cancer; Superficial Head and Neck probe, which is applied to hyper-parathyroid localization; and Daniel probe, for thoracic surgeons in video-assisted biopsy of sub-centimeter lung nodules. Additionally, it offers abdominal probe, Gamma-PET probe, and thoracic probe. The company sells its products principally in the US and worldwide through its representatives. RMD is headquartered at Watertown in Massachusetts, the US.