This simple to use tool will securely hold chisels and plane irons at the correct angle to the sharpening stone, and ensure a true square edge. Blade is centrally held in one of the two grooves in the vise-like aluminum jaws. The roller is 26mm (1″), with a maximum blade width of 82mm (3 7/32) and a maximum thickness of 7mm (9/32″).This is a different version of the more common gauge of this type. This version of this gauge has a large brass roller. The roller is twice as wide as the more common version making it more stable when rolling on the stone surface. The brass is corrosion resistant and will stand up to wetness forever.