Ring Stretcher And Reducer Size 1-15 - SFC Tools - 48-132 This Economy ring stretcher and reducer resizes ring shanks from size 1-15 (US sizes). It has 4-spline mandrel graduated in 1/4 sizes for smoothly and accurately enlarging rings. The reversible base plate has 16 reduction dies which can reduce ring shanks up to 12 mm wide by compression. This compact model measures 15.5 x 4.5 x 7.5 (39.5 x 11.5 x 19.0 cm).