3/8 inch wires come in a box of 6 - 12 inch strips.  Can be used with your Zutter Bind -it-All or Cinch binding machines.

Made to specifically round corners on heavy-duty materials, the Round-it-All will make rounded corners in chipboard, Zutter's acrylic, Canvas Artboard, Clipboard Wood, and multiple sheets of cardstock. Use your little rounder on single sheets and photos. R5 (Blue) makes a 1/4" corner.