Shape rings. Make consistant loops using the 3 barrels. Barrels measure: 5, 7, & 10mm (3/16 inch, 9/32 inch, & 3/8 inch). The lower jaw is covered with PVC tubing to prevent scratching or marring the wire. Features stainless steel heads and cushion grips. To harden wrapped loops, simply tap the wire with a nylon head hammer.