Marking gauges traditionally use a hardened point or an easy-to-lose graphite point to scratch a layout line, but this marking gauge from Gladstone tools instead uses a regular hexagon-shaped pencil to draw lines as far as 8″ away from the edge of your work.
Gladstone constructs this gauge from steel and places graduations every 1/16″ along the 10″-long, 1/4″-square bar for rough layouts. For more precise layouts you should probably check the scale against a precision steel rule.
You can find this marking gauge on Gladstone’s website for $13.
Pencil Marking Gauge [Gladstone Tools]