Wallach Disposable Os Finders Set (3) 920019. Disposable Os Finders - 3 Convenient Sizes in a Sterile Pouch. Os Finder (single notch) locates and opens external os. Canal Finder (two notches) dilates the cervical canal. Fundus Finder (three notches) sounds fundus and determines uterine depth. 3/SET, 10ST/BX. Priced per box of 10 sets. FREE Shipping!