Marking gauges are the best tool for layout work because they provide a crisper cleaner line than a pencil. This iGaging digital wheel gauge does everything a traditional marking gauge does, plus you have a digital readout. But, this would be a top-quality marking gauge, even without the digital. It has a large fence, smooth operation, and a substantial feel.
The large bright display reads either in 1000th of an inch, fractional inch, or 100th of a millimeter. The screen shuts off after 5 minutes of inactivity to preserve the battery.
You will find a digital marking gauge to be surprisingly useful. When you know a previous setting, you can return directly to it. Knowing the width of a board, you can divide by 2 to mark the exact center. You can zero the readout at any point. For mortising, you can mark one side of the mortise then zero the gauge, move its cutter the width of the mortise and mark the other side of the mortise from the same face. There is no better wheel marking gauge on the market.