This product in display is Deluxe Ring Stretcher. This deluxe ring stretcher includes 16 individual dies : (10) “V” grooves + (6) “U” grooves Reversible base plate with 16 total reduction dies Stretches/reduces ring sizes (1 to 33) & bands up to 12mm Dimensions: 17.5” x 4.25”x 7.25”Stretch and resize your stone set rings Stretch and resize your stone set rings without straining the stone settings or disfiguring the prongs with this ring stretcher set—contains an assortment of 16 rollers that will accommodate most ring styles. Product features: Dimensions:17-½” x 7-¼” x 4-¼” (16) Rollers ○ 10 “V” grooves ○ 6 “U” grooves Reversible base plate with 16 total reduction dies Stretches/reduces ring sizes (1 to 33); bands up to 12mm. This device simply works by rolling out the shank to stretch the metal and it will then stretch the ring but avoids loosening any prongs or stone settings.