A hand-held manual surgical instrument intended to be used during heart valve repair or replacement that enables evaluation of the valve opening (patent annulus) into which the appropriately sized annuloplasty ring or replacement valve will be implanted. It is typically available as a set of round tapered sizers in a range for the aortic, mitral, or tricuspid valve; it may include an attachable handle which may also be used to assist implantation. This is a single-use device.