You're looking at a brand new Seiwa circular O gouger leather tool from Japan. This high precision gouger is made from high-carbon steel and designed to leave a circular gouge in leather for creasing and folding.
Its also great for gouging recesses for filler for embossing, or magnets that make for a great hidden clasp. Not only does this O Gouger have a removable blade, but the handle can also fit any standard sized swivel knife blade! Tighten the grub screw to fix the blade or leave it loose to allow it to swivel in place offering you the ultimate in versatility.
Replacement blades available. The blade is easily replaceable so this tool will give you years of use.
The diameter of the hole in the circular blade is 4mm (0.16 inches) and the overall width of the blade is 5.2mm (0.2 inches).