Abstract: A spacer for positioning rods and wire in concrete is disclosed. In some embodiments, the spacer includes first and second saddle portions joined together via a connection mechanism. Spacing members are joined with the first and second saddle portions and first and second outer edges are joined with the spacing members opposite the first and second saddle portions. A conforming fixed centering tab having a centering groove is joined with the first saddle portion at first and second ends. An adjustable and conforming centering flap is joined with the second saddle portion at a first end via a hinge connection and includes a free second end opposite the first end. The centering flap has a length greater than a width of an opening of the second saddle portion. The connection mechanism is joined with the spacing members adjacent the outer edges for pivoting the first and second saddle portions.