Any instrument used for examination of hollow organs and/or canals. Most are bivalve or duck-bill shaped, consisting of two blades that can be separated or closed to facilitate the duration of the examination. The vaginal speculum is used to facilitate gynecological examinations and procedures. There are two primary types of vaginal speculums with the flatter, narrower version called a Pederson speculum and a wider, more curved design called a Graves speculum. Speculum may be reusable (e.g., metal) or disposable (e.g., plastic) and come in various sizes.